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334 from a 305?

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Old Oct 15, 2006 | 05:04 PM
  #1  
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From: Manchester, TN
Car: 1984 Camaro z28/SC
Engine: 355
Transmission: T56
Axle/Gears: 9bolt 3.89
Some questions

Last time I asked a question on here, I wanted a big cam, but didn't know anything about stall converters, and vacuum, plus I wanted it fairly streetable. Now the car will just be a weekend cruiser but not a daily driver. I'm also not looking for max HP gain, to me sound is a little more important than the HP. I will not be racing it.

Edit: I'm going to build a 350 instead of a 305...
I was thinking about boring my 305 out .030 over and then putting a 400 crank to get a 334. Would this be worth investing into or should I just get a 350?

Also about the cam, I was going to go with a streetable fairly smooth idling cam, but I don't think I'm going to go that route anymore. I just want a rough, lopey, rumpity idle. Yes, I do realize it will call for better heads, bigger stall, and less vacuum at lower rpms, rear axle, etc.

Hmm... I don't know much about this idea but I heard the idea and had to ask. Diesel engine make low vacuum, and have a belt driven vacuum pump for brakes and such. Is this correct? And could I put one of those on my car, if it has low vacuum(if I need to that is) It would be a lot cheaper than buying the ones for $450-500 or those brake boosters with the added vacuum control or w/e it is.

I have my mind set on either the Isky 244/244 @.050 and with 108 LSA, or a 247/247 with 108 LSA. About what would those cams call for in the line of idle speed, and stall speed?

http://www.iskycams.com/onlinecatalog.html
(scroll down to chevrolet V8 and click the 86-87 for the complete specs on the cams.)

Also what if I got the exact same cam(244/244) with 114 LSA, what would change, just the idle speed? and most of the cams I see have bigger exhaust the intake, would there be any difference in idle speed and stall speed, if it was a 244/254 instead of 244/244? Also what change does a higher lift do to idle lope, speed, or stall speed? I'm trying to get the best idea of what all the specs on a cam really do since there are so many options, maybe I could go a little smaller but still have the exact idle I want.
By any chance, does anyone know the specs of the cam that came in the 68 SS 350, something like a 292 cam or something?

I'm doing the dual exhasut from the hedman LT's out past a rear wheels with a 45 degree bend to end it. I'm debating whether I should put an H-pipes or not. Before the tips will be Chambered Exhaust, not sure which company I should choose from maybe someone could help me with that as well.

Keep in mind that I'm not worried about gas mileage, streetability, or max HP gain, and also that I'm reworking the whole engine, to match the cam I choose.

Last edited by JimmyDavidson; Oct 28, 2006 at 01:29 PM.
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Old Oct 15, 2006 | 05:28 PM
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Why are you bothering with the 305 block? If you really want that cam and supposedly are going to get decent heads to match, you are going to need to dispose of that block in the nearest dumpster and get at least a 350 or 400 block to start with.

Anyway, a 350 crank is going to get you... 305 cubes. They are both the same stroke.
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Old Oct 15, 2006 | 05:36 PM
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If you put a crank with the stroke of a 350 into a 305, you get..... <drum roll please> .....

a 305!!! <insert cymbal crash here>

If you put a crank with the 400 stroke into a 305 block, and bore the block .030", you get a 334.

If you spend $200 less than that, and just go to the junkyard and get a 350, you'll get more power for less money, with less trouble.

The 334 is a VERY BAD usage of money. Any time you can pay less and get more, it beats paying more and getting less. And for the "argument" that you "just want to do something different", do you think it would make very much sense to go to the grocery store and get a pound of meat let's say, and think to yourself "I just want to be different; so instead of paying $3.79 for a pound of this meat, I'll pay $4.19 and I'll only get 15 ounces. Yeah, that way I can be different". Would you do that? Well that's what a 334 is.

If all you want is sound, I'll record a REALLY FAST car, and send you the MP3. But if you want to build a motor, that's a whole different matter. Any idiot can jam a big cam in a motor and make it "sound" like it has a big cam in it (duh); it takes a bit more intellignece to get one to run good.

But the 334 thing is even more basic than that. It's just plain stupid, economically. Jam your big cam into a 350, it'll cost you less anyway, and you'll get just as much "sound".
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Old Oct 15, 2006 | 06:02 PM
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From: Manchester, TN
Car: 1984 Camaro z28/SC
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Axle/Gears: 9bolt 3.89
Ok that's what I wanted to hear, 350 is the best choice I can go with I guess, and yeah I meant the 400(3.75 stroke) crank dont know why I said 350.

And about the cam, many older cars ran good from that era, so that's good enough for me. I don't care about performance just a good sounding weekend cruiser. 300-350 hp is about what I'm shooting for. I'm taking suggestions for combos(that include one of those two cams) that will give me that but also have the idle I want.

I should probably go ask my question somewhere else as well because I doubt I'll get any straight answers here. Like I said, I'm not shooting for the best ET in the 1/4 mile, and this won't be a daily driver, I just want some grunt and decent power, just like back in the 60's.
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Old Oct 15, 2006 | 06:20 PM
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You can get straight answers here, but you won't always hear what you want to hear. Most people here are trying to help you be the fastest, not sound the best. Ask questions in the "auto detailing and appearance" or the "theoretical and street racing" board if you want to know more about how it looks/sounds, and are ok with going slow. (not to be harsh).

That's what I thought, in reference to old school setups. "I don't need those fancy gizmo's like a 1 piece oil pan seal, or a roller cam, or a .... If it made a car fast in the '80s, thats good enough for me". I mean, honestly, some high perf parts are pretty damn cheap if you don't need the cream of the crop parts right? So that's what I did.
.
.
.
However, in the old days, it was normal to have to reset settings, fix leaks, add oil, etc, at EVERY gas fill up. Now people take it for granted that you can get super high quality parts, and get the car to be like a brand new car - Ie, it doesn't burn a drop of oil (gapless rings for example), you don't need to gamble to get a leak free engine (rubber/1 piece gaskets, compared to old cork stuff), etc etc. I cheaped out and now i'm chasing down leak after leak after leak. It gets frusterating.

Anywho, that's my rant for today, stay tuned for tommorow's

If you get a lumpy cam, in a decent motor, and tune it right, you'll get upwards of 400HP. If you get a smaller cam, it'll be better on gas, easier to drive, not sound lumpy, and make the 320ish HP that you want.
Look at some other members combos, and ask them if they'd do it again, or if they recommend you go that route. A few i'd recommend asking:

Tuned port335 - has a 305 stroker. Good power, but on TPI, so not totally applicable.

mwnova66 - has a big cam in a 305. Lumpy by mosts standards. He REALLY knows how to tune it though, so it's "streetable". Upwards of 400HP.

Look in people sigs for videos/sound clips, and ask them what they've done to their car. I think you don't really need the super lumpy giant cam sound. What I mean is, a moderate cam, **with choice exhaust**, will *sound* very nice, and still be worth driving.

I have a compxe268. It's barely noticeable as an aftermarket cam. With my stock muffler, only a somewhat knowledgeable person (ie, not my mom) can tell it's a cammed motor. I can still drive it through a parking lot without it stalling. Now if/when I put on a flowmaster 80, or dynomax ultra flow, or some glasspacks, it'll idle like the beast is loose, and WOT will sound awesome.

ps. a simple (leaky) electric cutout can make any car sound pretty awesome. IMHO i've heard a stock LG4 with electric cutout, and I really liked the sound.

Hope some of my random mumbling has helped.
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Old Oct 15, 2006 | 06:56 PM
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From: Manchester, TN
Car: 1984 Camaro z28/SC
Engine: 355
Transmission: T56
Axle/Gears: 9bolt 3.89
If I had the complete specs from the older cars(complete cam specs, stall spec, engine specs, the whole works) It'd help me with my decision, but I can't seem to find everything I need.

I dont want to go with a moderate sized cam(221-232) and have to try to get it to sound "decent". I dont care if it has more than 350 hp, the more the better. I want it to at sound something like this( when he puts it in drive)

http://youtube.com/watch?v=racxsZFOWUk

Although mw66nova does have a big cam, the LSA was something like 114.. which makes the idle smooth? The only member that I know about that had a nice cam was Traxion's old Iroc that he sold to 92 Formula?

I can't really think straight right now, but all I know is that the cam and rumpity idle is a must.

Last edited by JimmyDavidson; Oct 15, 2006 at 07:05 PM.
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Old Oct 15, 2006 | 07:14 PM
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Originally Posted by JimmyDavidson
If I had the complete specs from the older cars(complete cam specs, stall spec, engine specs, the whole works) It'd help me with my decision, but I can't seem to find everything I need.

I dont want to go with a moderate sized cam(221-232) and have to try to get it to sound "decent". I dont care if it has more than 350 hp, the more the better. I want it to at sound something like this( when he puts it in drive)

YouTube - My car idle and take off

Although mw66nova does have a big cam, the LSA was something like 114.. which makes the idle smooth? The only member that I know about that had a nice cam was Traxion, but I dont think he goes here anymore.

I can't really think right now, but all I know is that the cam and rumpity idle is a must.
Back around '82 I had a '68 Camaro with a target master 350 and quadrajet (never cared for Holley much) bolted to a m21 with 373 gears. I installed a .485 lift /.310 duration bump stick in it and it not only sounded awesome but ran really well. I had tail pipes that ran out to the rear bumper which was rare in those days 'cause the norm was to bolt a set thrush glass packs on the headers and that was their exhaust system. On a cool morning it would actually blow smoke rings out the tail pipes when at idle. It was cool to see 8 or 10 smoke rings rise from each tail pipe before they vanished.

The thing is, a car of that era didn't require a lot of vacuum. All I had to do was add a vacuum canister and I was good to go.
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Old Oct 15, 2006 | 07:52 PM
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Comp XFI 280, its 232/236 113LSA
http://home.earthlink.net/~chris.foster/GPrev1.wav

It'll run better than that Isky, made 331 at the wheels with a stock runner and plenum TPI.
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Old Oct 15, 2006 | 08:04 PM
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Hmm.. Sounds pretty good. I'll keep that in mind. Have to get one for non-fuel injection though.

Last edited by JimmyDavidson; Oct 15, 2006 at 08:08 PM.
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Old Oct 15, 2006 | 08:20 PM
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Car: 1988 Trans Am GTA
Engine: 350 4BBL
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Originally Posted by JimmyDavidson
I can't really think straight right now, but all I know is that the cam and rumpity idle is a must.
You sound just like me! 114 LSA's are for wussies. I have an Isky 280 in mine. 224/224@.050 108' LSA with .465 lift on 1.5 rockers.
Here's the IDLE with open exhausts.
Here it is at 6500 RPM. (wait for video to load)
Build what you WANT!
The most important thing about a sports car is how it makes you feel.
Using 10:1 - 10.8:1 C/R, this cam gives you ONE pump of power brakes and some power below 2000 RPM. I think it's about the upper limit for streetable.
p.s. you have to be over 40 years old to drive it.

Last edited by Supervisor42; Oct 15, 2006 at 08:23 PM.
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Old Oct 15, 2006 | 08:27 PM
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Originally Posted by madmax
Comp XFI 280, its 232/236 113LSA
http://home.earthlink.net/~chris.foster/GPrev1.wav

It'll run better than that Isky, made 331 at the wheels with a stock runner and plenum TPI.
I've got this same cam in a 10.5:1 312 (.040" over 305) with ported ZZ4 aluminum heads on it. 1 3/4" x 3.5" headers, BBC TBI unit on a Holley Projection manifold, EBL running the show. 423 FWHP @ 5,900.


I had to add the slideshow of pictures to make it into a movie, to go onto YouTube.

YouTube - 400 FWHP TBI 312
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Old Oct 15, 2006 | 09:25 PM
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From: Manchester, TN
Car: 1984 Camaro z28/SC
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Transmission: T56
Axle/Gears: 9bolt 3.89
Originally Posted by Supervisor42
You sound just like me! 114 LSA's are for wussies. I have an Isky 280 in mine. 224/224@.050 108' LSA with .465 lift on 1.5 rockers.
Here's the IDLE with open exhausts.
Here it is at 6500 RPM. (wait for video to load)
Build what you WANT!
The most important thing about a sports car is how it makes you feel.
Using 10:1 - 10.8:1 C/R, this cam gives you ONE pump of power brakes and some power below 2000 RPM. I think it's about the upper limit for streetable.
p.s. you have to be over 40 years old to drive it.
Thats the kinda post I was looking for. Now I just have to know what the 244/244@.050 108Lsa and the 247/247@.050 108lsa will require for normal idle rpm. Anyone know the answer to this?

It says 2500+ stall on both cams, a 2500-2800 stall converter would work, correct?
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Old Oct 15, 2006 | 09:39 PM
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Originally Posted by Fast355
I've got this same cam in a 10.5:1 312 (.040" over 305) with ported ZZ4 aluminum heads on it. 1 3/4" x 3.5" headers, BBC TBI unit on a Holley Projection manifold, EBL running the show. 423 FWHP @ 5,900.


I had to add the slideshow of pictures to make it into a movie, to go onto YouTube.

YouTube - 400 FWHP TBI 312
FRONT WHEEL HORSE POWER?
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Old Oct 15, 2006 | 09:39 PM
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I'd say either one would idle at about 1000RPM in drive. Higher in park or neutral i'd think. You'll need full timing at idle, lock it out.
This is in a 350, in a 305 it'd be a nightmare to drive.

Part of the exhaust sound of that chevelle (the hollow tinny sound) is the muffler. That gives it the tone. I'd be curious to know what cam is even in it, I don't think it's that huge.

FWHP - Fly wheel horsepower.
Kinda like BHP - brake horsepower.
horsepower at the crank basically.
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Old Oct 15, 2006 | 09:43 PM
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Thanx Sonix, never seen the ab. before....
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Old Oct 15, 2006 | 09:48 PM
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gee, you edited your first post. Now the first few responses seem kinda stupid.

forgot to mention, summit makes a vacuum reserve can, the non-flashy one is only $30. Nice coating gets it up to ~$50. That'll take care of your brakes with a big cam.
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Old Oct 15, 2006 | 09:53 PM
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Car: 1984 Camaro z28/SC
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Originally Posted by Sonix
I'd say either one would idle at about 1000RPM in drive. Higher in park or neutral i'd think. You'll need full timing at idle, lock it out.
This is in a 350, in a 305 it'd be a nightmare to drive.

Part of the exhaust sound of that chevelle (the hollow tinny sound) is the muffler. That gives it the tone. I'd be curious to know what cam is even in it, I don't think it's that huge.
1000 sounds about right. Definately leaning toward a 350 now though. What exactly do you mean by "full timing at idle, lock it out"

Yeah, its the dual exhaust and muffler that give it the hollow sound. I was just refering to the rumpity sound. And yeah it doesn't seem too huge to me either, it only the the lopey-ness that I want when he shifts it into drive and the idle rpm goes down.

Edit: Yeah I would have left the stuff about the 334 in there, but then I'd still be getting responses about how bad a 305 is :S

Last edited by JimmyDavidson; Oct 15, 2006 at 10:16 PM.
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Old Oct 15, 2006 | 10:23 PM
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From: Arab, Alabama
Car: 1988 Trans Am GTA
Engine: 350 4BBL
Transmission: 700R4
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Originally Posted by JimmyDavidson
...I just have to know what the 244/244@.050 108Lsa and the 247/247@.050 108lsa will require for normal idle rpm. Anyone know the answer to this? It says 2500+ stall on both cams, a 2500-2800 stall converter would work, correct?
I didn't realize you were looking at solid lifter cams. As for their stall recomendations: this would be the minimum required in order to be able to put it in drive and not have it DIE. If you want to leave the line you'll need a little higher stall than that.
I have a 2400 stall in mine and it's just enough to keep the car from lurching when you put it in gear.
As far as a "normal idle RPM" goes, if you consider 1000 rpm normal
(1100 with A/C), it will be plenty nasty with either of those. (slightly better in a 383).
I'd put a 2800 stall with the 244 and a 3200 with the 247.
The engine with a 244 would need to be built to spin to 6700 rpm and the 247 to 7200.
At the track, that is...
I still think they are both above being streetable, especially the 247.

Last edited by Supervisor42; Oct 15, 2006 at 10:38 PM.
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Old Oct 15, 2006 | 10:45 PM
  #19  
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Ok thanks for the information. I'll probably go with the 244 then. With a 2800 stall, lets say I put it in drive, at what rpm will I have to "rev" it up to get it to start grabbing and start moving the car, or will it automatically start grabbing?
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Old Oct 15, 2006 | 10:52 PM
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Depends on how the converter is setup. My 10" 2,800 would roll out at light throttle with as little as 1,000-1,200 rpm.
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Old Oct 15, 2006 | 11:50 PM
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Yea, common misconception is with a 2800RPM stall, you have to bring up the revs to 2800rpm to get moving. In a parking lot, you can tell that would be a nightmare.

That's not how it works though. That means if you lift your foot off the brake, and hammer the gas to the floor, the RPM the motor will hit before the car moves off that dime you parked it on, is the stall speed. You're thinking "but that depends on a lot of factors, like engine power, car weight, etc right?" right. Thats why they say "2400-2600RPM stall speed" is the rating of such and such convertor. Throw a certain convertor in a 305, or a hot 383, it'll act differently.

A good accurate stall speed on a convertor, is going to be custom made by the expert companies. And cost an arm and a leg, 'specially in a high #'erd stall application like that.

That's why I drive a stick, clutch is the single factor I have to screw with, and it's cheaper than a convertor too

oh, you'll need more timing to get it to idle. Otherwise you'll have to open up the butterflies a ton, and it'll run so rich at idle it'll burn your eyes, and have carboned up spark plugs between gas fillups (which are going to be frequent).
Just one of the many keys of knowledge in order to get a big cammed motor to run at all on the street. The better (more knowledgeable) the tuner, the more cam you can run on the street comfortably.

Don't worry, you've got lots of time to learn the little details.

Stekman says he gets 5.5mpg on his 400cid with a big cam. You'll get around that. You comfortable with that?
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Old Oct 15, 2006 | 11:58 PM
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Dont waste your time trying to run dual exhaust with hedman long tubes. They tuck up to tight. I have tried several times and lost the battle everyone. I even tried a y-pipe a couple of times. I dont think it can be done.
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Old Oct 16, 2006 | 06:01 AM
  #23  
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Yeah, 5.5-10 mpg somewhere in there I was expecting. The main reason that it will not be a daily driver.

I've seen a few applications with hedman lt's, so Im going to try something like that. Look at Mw66nova's exhaust setup.
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Old Oct 22, 2006 | 10:51 PM
  #24  
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From: Manchester, TN
Car: 1984 Camaro z28/SC
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Hmm, I was looking through Comp Cams, and found the 294S 248/248@.050 525/525 on 110LSA.. would that be any better than either of the Isky cams? What in terms of idle lope and performance? Would it be possible to have a 9.5:1 CR with this cam incase of blower application? Or would it have to be around 10.5:1?

I got a nice '73 350 in nice shape the other day, so that is the base I'm using. We'll be putting new heads(probably cast iron), intake, and carb. Any suggestions to keep up with the cam?

And I thought about it and I think I going to get a 5-speed, so I wouldn't have to change the converter incase I decide to go with a little smaller or bigger cam.

And if I decide to go with a blower(later on, dont have the money now) would I have to change the cam to a special blower cam?
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Old Oct 22, 2006 | 11:00 PM
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You want to decide now if you're going to supercharge it or not. You don't just swap the cam, it needs to be a whole new motor, or else your gains will be dismal, ie, not worth the cost.

248/248 would need above 10:1, 10.5:1 I'd say. No, 9.5:1 won't cut it. It'd be SUPER lame at low RPMS.

You'll need lots of cylinder head flow to keep up with that cam. What's the budget?
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Old Oct 23, 2006 | 06:25 AM
  #26  
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Alright that's what I figured. I need to try and keep a low budget, but if there is a part that is better for a little more money I'll spring for it. I wanna do it right the first time. And yeah I figured I wouldn't be able just switch the cam, I was just wanting to know how much of it would be able to stay, but either way I don't think I'm going supercharged.

What would the difference in idle lopiness, and performance be between the Isky 247/247@,050, 480/480 lift, 108LSA and 248/248@.050, 525/525, lift 110LSA

Thanks for all the help so far.
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Old Oct 23, 2006 | 04:12 PM
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Car: 1982 Trans-Am
Engine: 355 w/ ported 416s
Transmission: T10, hurst shifter
Axle/Gears: 10 bolt, true-trac, 3.73
They'd be quite similar IMHO. The 2nd might make a tad more power due to the increased lift, if your heads can support it.
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Old Oct 23, 2006 | 07:02 PM
  #28  
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From: Arab, Alabama
Car: 1988 Trans Am GTA
Engine: 350 4BBL
Transmission: 700R4
Axle/Gears: 3.27
Originally Posted by JimmyDavidson
What would the difference in idle lopiness, and performance be between the Isky 247/247@,050, 480/480 lift, 108LSA and 248/248@.050, 525/525, lift 110LSA Thanks for all the help so far.
Not to disagree with Sonix but I think the difference in Idle between the two would be quite pronounced. The 108 is going to be not quite streetable and I think the power brakes will be lame even with a canister unless it's a stop coming down from >3000 rpm. Do the math about how much overlap this cam has. The good news is: it'll scream all the way to 6800. (Damn, I love that sound)
The 110 would probably be streetable, but barely.
As for using a clutch to live with a high duration cam, think again.
Ask one of the other board members about his post wanting a way to keep from smelling "clutch burning" when he turns around and backs into a parking place. He had to keep the rpm above 2000 just to keep from killing the engine.
Mmmm, toasty!!!
This is one case where a stall converter can make a big cam "livable" on the street.
edit: Oh yeah, the 108 would have a nastier lope too.

Last edited by Supervisor42; Oct 23, 2006 at 07:09 PM. Reason: added ps.
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Old Oct 23, 2006 | 08:24 PM
  #29  
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From: Manchester, TN
Car: 1984 Camaro z28/SC
Engine: 355
Transmission: T56
Axle/Gears: 9bolt 3.89
I talked to my dad(keep in mind he does not know the details of cars, but had experience when he was younger) about the burning clutch deal. He said that you have to slip the clutch, and the when you have a big cam with high gears that it will be hard to move around but with lower gears its not so bad. Is there any truth to this?

I'd definately pick the Comp Cam for sure, but I dont know about the added $60-70 price of the comp cam compared to the isky. would it be worth 60-70 for "more streetability" and 18* more lift? The comp cam runs good to 6500 and the isky to 6800. I'll check about the overlap and see if I can get a better compararison of the two cams.

Edit: The Comp cam has 74* overlap and the Isky has 66* So would the comp have more roughness? Or is it still the Isky?

Last edited by JimmyDavidson; Oct 23, 2006 at 08:45 PM.
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Old Oct 23, 2006 | 08:56 PM
  #30  
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From: Calgary, AB, Canada
Car: 1982 Trans-Am
Engine: 355 w/ ported 416s
Transmission: T10, hurst shifter
Axle/Gears: 10 bolt, true-trac, 3.73
The Comp cam has 74* overlap and the Isky has 66*
Where'd you get those #'s from? Just curious?

The thing with the stickshift (and bigger cam) is that you can't let it completely into gear at 800RPM, like you can with a stock cam, or else it'll jerk and chug and buck like crazy, and you look like a tool in the parking lot. You have to run it at 1200RPM (or higher, whatever the cam is...) at least, so you end up just BOOKIN' IT across a parking lot, or you end up riding the clutch.

Or you end up letting the clutch up, getting going a bit, then putting in the clutch, coasting, rinse and repeat. Lemme tell ya, with a mechanical clutch linkage, that gets old pretty fast. I'd hate to have to drive my car in traffic, ugh! And I don't really have a ton of cam.

Anyway, you have an auto, so this is kinda moot.

Supervisor - you think that 2* in LSA angle difference really would be noticeable? I mean, would a degree in LSA change be like 2* in duration @.050" ? Or...? I have a hard time wrapping my mind around how it can be a seperate value from duration @ .050", yet still effect the powerband etc etc.
So I just went back to reading the david vizard book - SBC camshafts and valvetrain. It's making more sense each time I read it LSA should have a quadruple effect on overlap.
So that 2* would be like 8*... interesting.

Last edited by Sonix; Oct 23, 2006 at 09:10 PM. Reason: added info
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Old Oct 23, 2006 | 09:09 PM
  #31  
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From: Manchester, TN
Car: 1984 Camaro z28/SC
Engine: 355
Transmission: T56
Axle/Gears: 9bolt 3.89
Yeah that's pretty much what he said. And I dont exactly have the 700r4 yet, so I could get either the 700r4(which isnt working but the guy doesnt know whats wrong with it) or a 5-speed.

I rechecked the figures on the overlap... and the Comp is 74* @ 0.015 and the Isky is 66* @ 0.020. I'm not sure which has more overlap. Hmm...
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Old Oct 23, 2006 | 10:54 PM
  #32  
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From: Arab, Alabama
Car: 1988 Trans Am GTA
Engine: 350 4BBL
Transmission: 700R4
Axle/Gears: 3.27
Originally Posted by Sonix
Supervisor - you think that 2* in LSA angle difference...
So I just went back to reading the david vizard book - SBC camshafts and valvetrain. It's making more sense each time I read it LSA should have a quadruple effect on overlap.
So that 2* would be like 8*... interesting.
Ding Ding! You're finally getting it. Lobe Separation Angle is degrees between the lobes centers on the cam.
It is in CAM degrees not CRANK degrees. Exhaust closes 2 degrees (crank) later. Intake opens 2 degrees (crank) sooner. Overlap increases by 4 degrees. This is NOT like adding 4 degrees more duration. The intake is already open long before top dead center. The exhaust valve is still mostly open. The more overlap you have the longer both the intake and the exhaust ports are connected together during the end of the exhaust stroke. During slow engine speed (rpm) this causes exhaust to back up into the intake momentarily before the piston starts downward. The whole idea is that this overlap is very short to keep the "backpumping" from spoiling the intake vacuum completely. As you add duration you add to this overlap because each valve is opening sooner and closing later. When you move the lobes closer together this makes a bad problem even worse very quickly.
Check those overlap numbers again using advertized duration at ".000" lift.
The rest is just more rant.
So why have a 108' or 106' LSA cam anyway?
The answer is how headers work.
When the exhaust pulse is zooming down the primary pipe, the piston starts to slow down rapidly at the end of it's stroke. When this happens, the momentum of the exhaust draws a vacuum in the combustion chamber before the piston has to go back down to start to draw from the intake. This is where the nasty overlap begins to work in our favor. Before, the more the valves were open during overlap the more we were "back-pumping" into the intake at idle. Now, at higher speeds the high vacuum is coming from the headers and the intake has low vacuum. Instead of backpumping we now have "super-scavenging". This is essential for high rpm power.
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Old Oct 24, 2006 | 01:26 AM
  #33  
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From: Grand Rapids, MI
Car: Z28
Engine: Sb2.2 406
Transmission: Jerico 4 speed
Axle/Gears: Ford 9" 3.60
Is solid roller out of the question?
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Old Oct 24, 2006 | 04:30 PM
  #34  
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Car: 1984 Camaro z28/SC
Engine: 355
Transmission: T56
Axle/Gears: 9bolt 3.89
Nah Im gonna stick with the solid flat tappet.

Hmm. I dont know how to calculate overlap. Comp and Isky gave the Intake Opening Degrees and Exhaust Closing Degrees and different lift. Unless theres another way to measure it. Any suggestions?

Would the comp cam be the best all around cam? Considering it has more lift and a tad more streetability.
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Old Oct 24, 2006 | 07:02 PM
  #35  
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From: Arab, Alabama
Car: 1988 Trans Am GTA
Engine: 350 4BBL
Transmission: 700R4
Axle/Gears: 3.27
Originally Posted by JimmyDavidson
Unless theres another way to measure it. Any suggestions?.
I didn't take into account that the comp had more duration (294) than the Isky (282). The comp may have more overlap.
Originally Posted by JimmyDavidson
Would the comp cam be the best all around cam? Considering it has more lift and a tad more streetability.
The Comp will be slightly better at low rpm (meaning less than 2500) than the Isky. If you don't plan to spin the engine to 6800 rpm the Comp is a better choice. On my opinion neither one is "best all around" because they are above streetable... Which I think is what you're looking for.
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Old Oct 24, 2006 | 07:10 PM
  #36  
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From: Manchester, TN
Car: 1984 Camaro z28/SC
Engine: 355
Transmission: T56
Axle/Gears: 9bolt 3.89
Ok, thanks for the help, I appreciate it.

The comp has 1* more @ .050 than the Isky. And 18* more lift. So I'm not sure. but either way it'll be fairly close so I'm not worried about that anymore.

I just want a car that I can drive to car shows, or out on a weekend cruising. I'll probably get another car for daily driving purposes.
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Old Oct 24, 2006 | 07:40 PM
  #37  
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Originally Posted by JimmyDavidson
Ok, thanks for the help, I appreciate it.

The comp has 1* more @ .050 than the Isky. And 18* more lift. So I'm not sure. but either way it'll be fairly close so I'm not worried about that anymore.

I just want a car that I can drive to car shows, or out on a weekend cruising. I'll probably get another car for daily driving purposes.

If you're set on that size cam, here's a budget cam in that range that I have used before with good results in 10.5 - 11:1 406s

Intake@.050"-Exhaust@.050"-Intake Lift-Exhaust Lift-Intake Center-Exhaust Center-Overlap

246 --------------- 246 -------- 0.498 ----- 0.498 -------106--------- 110 --------- 65 degrees (Lobe spread is 108-degrees)

Competition Products-Elgin, Camshaft Only, Chev SB, Mechanical, FT, 246/498,
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Old Oct 24, 2006 | 10:27 PM
  #38  
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just gonna throw this out there. If you are new to the game, a solid flat tappet cam might not be the best choice. They need periodic lash adjustment, along with better valve train parts. A solid will need at least a valve spring with 140# on the seat and 400# open pressure, which will require a quality roller rocker, screw in studs, guide plates, better push rods. If you are going to do this to a cast iron smog head, this just becomes a flat waste of time and money. The guys on this board will give you some great advice and input, but I don't think a solid is a good choice imho. If it were me, I would focus on building the biggest engine I could afford. I have a friend who budget built a 383 with cast iron vortecs and a relatively mild hyd. cam that scares the crap out of me every time he takes me for a ride. The car laid down 330 hp and 400 ft#s at the wheels, and will grab rubber in all 4 gears.
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Old Oct 24, 2006 | 11:16 PM
  #39  
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Car: 1991 Z28
Engine: 383 TPIS Mini Ram
Transmission: D&D Perf Viper/GM T-56
Axle/Gears: 3.73's Eaton Posi
I think its great that you wanna make the car what you want it to be, but honestly it doesn't sound to me that you have much business building a motor, or picking out parts for one. Please don't take that the wrong way I understand thats why your here, looking for answers. But remember one thing here you are getting a lot of opinion. I would be inclined to say that you are a prime candidate for a !!!CRATE MOTOR!!! God people its obvious that your tossing cam duration numbers at someone who isn't truely understanding what the hell your talking about. I would hate to see you spend money on parts and prepping a block (if you even get a good one to re-build), and have nothing work in your favor. Just flip to the Summit Racing catalog and pick up a long block 330hp 350 ALL BUILT AND MATCHED for way less than this land mine of a project is going to end up costing you. Make things simple for yourself, in other words don't open the hood of a car if you really can't work on it. I understand that anyone can read numbers online or from catalogs referring to camshaft duration lobe seperation etc... But honestly you have flip flopped so many times in this series of postings that it makes me question your common understanding of what these numbers are really going to mean once the engine is up and running. If you want great sound the 330hp 350 will sound awesome with a set of Hedman Hedders shorty style and maybe get them Jet-Hot coated. Get the y-pipe and a Flowmaster american thunder system. Problem solved!!!!! NEXT!!!

Last edited by smallblock383; Oct 24, 2006 at 11:28 PM.
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Old Oct 25, 2006 | 07:06 PM
  #40  
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From: Manchester, TN
Car: 1984 Camaro z28/SC
Engine: 355
Transmission: T56
Axle/Gears: 9bolt 3.89
Eh.. crate engine? screw that... A crate engine, would NOT have a good idle, and it may be streetable but Im not looking for a less than mild cam in an engine. You have a completely different look on things than I do. You think that high horsepower in a car that won't EVER be on the strip, needs major horsepower? Cause thats not what I think, I'm looking for a engine, that most likely wont be very streetable, but will sound good and run pretty good. I dont care about getting maximum horsepower out of a show car, or even a street car, its pretty much a waste to have 350+ hp on the street. It's like taking a shower with you clothes on, it just doesn't make sense.

I may not have the experience to back those numbers up, but I have a pretty decent knowledge of what they mean. Maybe I didnt know anything when I started this post, big deal, I know enough now to pick out a cam, with the right parts, tuning and everything else need to get the motor to run good(It will trust me). I had problems mainly with the cam because it is the most understood and most complicated peice of an engine.

Also why would I want shorty headers? For maximum street performance? No, I'm going with Hedman LTs and dual exhaust for "Show Car Sound"

So far, the only thing I agree with you about is the American Thunder system. I was going to go with something similar.

Sounds to me like you dont have much business posting in this topic, with answers that I didnt ask a question for. If your going to flame or post another topic saying that a crate engine is the way to go, you might as well not post, to try and keep the flames to a minimum.

Like you said I think the problem is solved. Tomorrow the block is getting sent off to get machined, bored .030 over, new cam bearings, and "homed(sp?)"

I'd still like to know the overlap of both cams, compared at the same lift, if someone would mind telling me.

@trlprk- I realize the work that goes into a solid cam(flat tappet by the way, no roller rockers) Most of the parts are going to be new, rockers, springs, pushrods, connecting rods, pistons, etc. Im getting new heads, not sure of which, but it will be compatible with the cam and other engine parts.

Again thanks Sonix and Supervisor42 for most of the help.
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Old Oct 25, 2006 | 07:35 PM
  #41  
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From: South Louisiana
Car: 92 RS
Engine: Built 355
Transmission: Built 700r4
Axle/Gears: 3.73's w/ stock axles
Listen to smallblock383. I was in the same boat as you. I knew what I wanted, but just didn't know exactly how to get there.

By the grace of God, I hooked up with this guy that builds engines and was able to sell off most of the expensive stuff that I bought that just wouldn't work in a street car. I've been into my project for a year and the engine is built and ready to go in. I've learned gobs of info, but I still don't have command of the knowledge enough to do the next build completely on my own.

As a matter of fact, I would have completely screwed up this one if it weren't for a good friend bailing me out (and this site). Guys like me will never know the vast ammounts of info that some people that have been building engines for twice as long as I have been alive for have now.

And about the crate engine....I know the idea sounds gay, but there are companies on the web that you can call and explain the same things that you have stated here and they will build you a custom crate engine for almost less than you can do it for.

Last edited by systalis; Oct 25, 2006 at 07:43 PM.
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Old Oct 25, 2006 | 07:38 PM
  #42  
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From: Calgary, AB, Canada
Car: 1982 Trans-Am
Engine: 355 w/ ported 416s
Transmission: T10, hurst shifter
Axle/Gears: 10 bolt, true-trac, 3.73
roller rockers are seperate from roller LIFTERS. You can / probably will have roller rockers.

homed -> honed.
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Old Oct 25, 2006 | 07:50 PM
  #43  
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From: Manchester, TN
Car: 1984 Camaro z28/SC
Engine: 355
Transmission: T56
Axle/Gears: 9bolt 3.89
Oh yeah, I probably will have roller rockers, I was thinking of roller lifters. I was probably a little harsh in my statement above, but someone judging me based on the assumtion that I had very little knowledge about anything, made me a little mad, but Im over it, so its whatever.

systalis-I see what you and smallblock383 are saying but I doubt it would be cheaper than what I'd could do it for. About how much would one of these custom engines(with all parts I would want on it) cost me?
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Old Oct 25, 2006 | 07:58 PM
  #44  
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From: Calgary, AB, Canada
Car: 1982 Trans-Am
Engine: 355 w/ ported 416s
Transmission: T10, hurst shifter
Axle/Gears: 10 bolt, true-trac, 3.73
Sadly, a crate shortblock is usually about the same price (or cheaper!) then machining what you have. It's not as much fun, if you thoroughly enjoy turning wrenches and learning, but if you want to be dead sure it's gonna work as advertised then...

You still throw on your choice of heads/cam, so those aren't effected by the fact that it's a crate. (Unless you buy a crate longblock or turnkey, then just buy new top end parts or something, but that's just silly...)
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Old Oct 25, 2006 | 07:59 PM
  #45  
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From: South Louisiana
Car: 92 RS
Engine: Built 355
Transmission: Built 700r4
Axle/Gears: 3.73's w/ stock axles
Man.. When I started my project, I had these sites saved on my computer, but thanks to my 2yr old son dropping my laptop, my hard drive crashed and I lost tons of info that wasn't saved.

I was looking at 383 longblocks for around $4000 with aluminum heads. The guy I talked to (I think this particular one was in Arizona) he didn't charge extra to change the cam if the cost of the cam wasn't more to him.

I'm throwing out that 4k number from what I can remember. I'll have to check again.
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Old Oct 25, 2006 | 08:05 PM
  #46  
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From: Manchester, TN
Car: 1984 Camaro z28/SC
Engine: 355
Transmission: T56
Axle/Gears: 9bolt 3.89
Ok, I'm going to stick with the block I have now. So, on average, what would a bore .030 over, installing new cam bearings, and honing, and hot tanking at a machinist cost? $235 sound reasonable?
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Old Oct 25, 2006 | 08:14 PM
  #47  
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Transmission: T10, hurst shifter
Axle/Gears: 10 bolt, true-trac, 3.73
If you're very lucky, perhaps.
Is that what your machinist quoted you?
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Old Oct 25, 2006 | 08:15 PM
  #48  
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Car: 92 RS
Engine: Built 355
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Axle/Gears: 3.73's w/ stock axles
The machining cost me more than that but it did have to spend a little longer in the tank than normal. The previous owner didn't like to change the oil much.

About the previous subject I posted....try this eBay

I know thats for a 383, but use it for refrence. I think this particular guy also has a website somewhere.

Last edited by systalis; Oct 25, 2006 at 08:21 PM.
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Old Oct 25, 2006 | 08:20 PM
  #49  
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From: Manchester, TN
Car: 1984 Camaro z28/SC
Engine: 355
Transmission: T56
Axle/Gears: 9bolt 3.89
Originally Posted by Sonix
If you're very lucky, perhaps.
Is that what your machinist quoted you?
Yeah, he said it would take about a week and a half, with everything I said above for $235. What would it normally cost?
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Old Oct 25, 2006 | 08:26 PM
  #50  
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From: South Louisiana
Car: 92 RS
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I'll have to look for my papers, but I believe mine was a little over $400.
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