vic_V8

I'm rebuilding the top end to the 305 HO (doesn't need it, but I pulled the motor to replace a timing chain)

the heads are the 416 castings, I'm gonna port them a tad, free flowing exhaust, 650 holley, edelbrock intake, etc...


the cam: hyrdralic, .489 lift, 216/217 duration

is this too much for a non-roller motor?

EDIT: i already have the cam lying around, and would rather not waste the money on another

jfreeman74

I would say no but I'm a TPI guy. I'm not sure how different the setups are when in comes to which cam works best. I am going to be going with a 218/224 or a 212/218 cam with Torquer 305 heads. I haven't gotten a lot of input from anyone as to which would be best. Have you tried calling CompCams? Their tech support is pretty good.

Tom84L69

I have a 230/230 duration .480" lift at .050" cam. It's in an L69 with ported heads and intake. The computer is not operating and I have a non cc q jet. runs very well. The cam should act the same in a 305 as it does in a 350 due to the fact that both engines have the same stroke.

Sitting Bull

The lift is too much for a stock head. Stick to the .460 region.

Or have your machine shop set it up for greater lift.

vic_V8

i was reading that the Lo3 could handle upwards of .480?

five7kid

iTrader: (14)

That's commonly said about unmodified Vortec heads.

If you're having the top end done, do it right. New valve springs & retainers, cut-down guides for positive seals, screw-in studs.

Any builder worth his salt will check seal to retainer clearance to verify the cam isn't too much.

zippy

it's too much only in the respect that you aren't gaining much by having that much cam. with the heads that came on that, you'll be losing as much as gaining.

ShiftyCapone

iTrader: (7)

Not true. The 416's are great heads and work even better when they are ported. The stock smoggers found on the LO3 on the other hand are just plain garbage.

Chris89GTA

iTrader: (2)

Not true. If you put the same cam in both a 305 and a 350 the cam in the 350 will act a lot milder, and have more street manners than the sam cam in the 305. Why? CUBES. Same goes for a cam in a 350 compared to a 383. In a 383 a radical cam in a 350 will act like a medium cam in a 350.

Tom84L69

No, stroke is the determining factor. If you were putting that cam into a 283, then it would be rougher, but a 305 has the same stroke as a 350. I'm relying on my dad for this one, a GM engineer, cause i thought it was cubes also.

Tom84L69

the 383 will be milder because it has a longer stroke than the 350.

Chris89GTA

iTrader: (2)

If that were the truth, then people would reccomend the same cam for all 305s that they recommend for 350s. Which is so not true. I would love to hear an explaination on why stroke would affect a cam and make it act the same in a 305 and a 350. No flaming intended here at all.

There are way to many people w/ experience that says otherwise.

jfreeman74

I am going to agree with everyone on this. The cams would definitely act different in different cars. Do you guys think that a 218/224 114LSA cam would work in a 305 TPI with Torquer 305 heads and a possible aftermarket intake or ported stock intake in the future?

Chris89GTA

iTrader: (2)

Sat and thought about this for a while, and sorry to say it, your dad is wrong.

Its about total airflow. Doesn't matter if its bore or stroke...more cylinder volume is going to demand more air and that's going to increase idle vacuum and make the cam act smaller in a bigger motor....not to mention the airflow needs at higher RPM.

Fast305

I have to agree with the GM engineer. Stroke is the determining factor as well as compression ratio. Compression probably has more to do with it than anything else. I have a friend that has an edelbrock performer cam in his new crate 350 8.5:1, it idles with 18 in/hg of vacuum @ 650 rpm. For those not knowing the performer has 204* & 214* of duration @ .050" lift, and .423 & .442 lift. I have the same exact cam in my 160,000 mile 305 ho, 9.5:1. It idles @ 21 in/hg @ 650 rpm. Point is that compression and stroke have more effect than cylinder displacement. Longer stroke= smoother idle & more vacuum. I could take a chevy 302 put the same cam in it and it would run more lopey than a chevy 307. The 307 would run more lopey than the 305. Stroke has alot to do with low speed behavior on engines. Airflow makes almost no difference @ low speeds and idle. Think about it the throttle blades are nearly closed= high vacuum and no air flow. I bet if you took a 305 and 350 built them the exact same, that both would run identical in respects to idle stability and idle vacuum. The 383 has a longer stroke than the 350 so it will be smoother. If you took a 377 (400 block & 350 crank) it would run alot cammier than a 383. One of my friends has what would be considered a huge cam for a SBC put in a Chevy 292 I6. The stroke on the I6 is like 4.125 or something around there. It idled real smooth considering it had a Crane cam with something like 310* & 320* advertised duration and something like .580" of lift, heres the kicker it idled @ 750 rpm with 13 in/hg vacuum. Put a cam same with the same specs in a 305 and it would idle like a stock car with maybe 5 in/hg vacuum. The guy had the thing in an RV of all things. It worked for him because it cruised @ 3,000 rpm @ 60 and had a turbo 400 with like a 2,500 stall.

Point is stroke has alot to do with how an engine will react to a cam. Compression is also a big factor. More cam means you need more compression. More stroke means that an engine will put out more low speed torque with a given cam which results in a smoother idle and more vacuum.


Here is some proof that a 305 tends to like the same cam as a 305. The powerband will be a little higher in a 305 due to the smaller displacement but it would be much smoother and idle better than it would in a short stroke motor of the same displacement (can we say 1967-1969 DZ 302)


Here is what lunati has to say about the cam in there 343 HP 305:

Lunati installed one of its Streetmaster hydraulic non-roller-tappet grinds that offers reasonable idle quality with just a touch of that performance "rump-rump" so dear to our hearts. At least that's how it behaves in a benchmark 350; the cam is a tad more radical in a smaller displacement motor. To compensate for the engine's small displacement, the cam was installed 4 degrees advanced, and uses 1.5:1 ratio long-slot rockers.

Why not use a smaller cam? Lunati says it's hard to move air through a small-bore motor with a restricted valve area like the 305. You need a bigger cam to make this small cylinder work, but there are limits due to the small displacement. Fortunately, the relatively long stroke for this displacement engine helps low-end torque, so the engine isn't all that cam sensitive.

http://www.goingfaster.com/spo/343hp305.html



Here is what Comp Cams has to say about camming a 305.

Competition Cams' current thinking on camming the 305 specifically is that it seems to like the same cams as a 350-- at least within the realm of relatively mild smog-legal grinds. On one hand, small valves require overcamming, but low displacement makes cams appear more radical. Yet the 305's 3.48-inch stroke permits overcamming to some extent, so the RHS "green" 305 ended up with it's biggest Pure Energy grind. 1.6:1 ratio Magnum Roller-tip Rockers were used to enhance lift.

http://www.goingfaster.com/spo/290hp305.html

I guess if you want to get technical everyone is right. A longer stroke= less of a chance of overcamming as does increased cylinder displacement. When you combine the 2 such as in the difference between 350 and 383 or 305 and 334 you could really tell a difference in low speed behavior.

Tom84L69

Thank you Fast305 for a better explanation than I could give.

Chris 96 WS6

Goingfaster.com.......OMG somebody is pulling out the black echo crap and using it as factual support for their argument? Bwahahahahaha....

You realize that guy never did ANYTHING to his car...it was all just pages and pages of speculation from a guy who could write well enough to get you to think he's right.

owned

Jesus.

It's not about stroke, compression, head flow, intake matching, engine size, solar flare activity, proximity to magnetic poles, or what your engines horoscope is.

The bottom line is that a given cam will be mildest in a motor that can pull the most vacuum with it at the lower rpms. It's the total picture that matters.

However, the biggest factor is probably compression and cylinder volume.

If all other things are equal, a 350 will always be more streetable with a more agressive cam than a 305.

Kevin G

LMAO!!!! I remember the days of endless ramblings... I would take anything on that site wth a grain of salt..

vic_V8

wow! I should have known better than to open a can of worms.

I guess I'll just put the cam in, and we'll all see

N8MAN1068

it looks like if all else fails, run the cam with some advance.

vic_V8

should I use 1.5 rockers? or 1.6?

Tom84L69

All I see after that long post is a bunch of speculation on everyone elses' part. That site he posted may not be reputable but it looked like decent info to me, plus it goes along with what I said before.

Is everyone arguing here because they think that they know what they're talking about?

Zepher

iTrader: (1)

I stuck a big cam in my 305.
At the time, I had no idea about engine parts compatibility, I was just looking at the numbers and chose the largest one for a TPI motor and a 5 speed.
I went with the Crane Cams Powermax 2050. Can't remember all the specs but I do remember .480/.454.
Here is a video of the car after I had the exhaust put on.
http://www.transamws6.com/video/ZepherWS6.mpg

Chris89GTA

iTrader: (2)

I think there are a ton of guys here w/ a ton of knowledge on the issue. My info is based on their personaly experience, and my own, plus that of respectable books out there by very reputable engine builders...

Fast305

My info came from personal experience as well as some solid info from others. If you look at the bottom of both articles the source was the Octobor 1993 Car Craft magazine issue. I certainly wouldn't call car craft a mediocre source. I also wouldn't call Competition Cams or Lunati Cams ignorant about cam selection facts. I know!!! If you don't believe stroke has something to do with cam selection, call the cam manufacturers and talk with the cam experts. I did when I choose my 305 cam. Crane cams told me that a 305 and 350 will respond very similarly when the same cam is used in both. Okay, still don't believe me, send in a cam recomendation form for a 305 and 350 in the same application and with the same specs. I bet the cam they recomend is either the same or real close.

About what was said above about vacuum. A longer stroke will give more vacuum (all other things being equal), which means it will have better driveability. More compression will also give better vacuum. More cubic inches also give better vacuum. Its the combination as I stated above. A 8.0:1 smog motor would barely run with a huge cam, on the other hand Nascar motors use about 12:1 or more and run great @ high rpm. Why do you think the 302 and 307 dissapeared in the mid 70s. The shorter stroke had trouble making torque when compression was dropped into the 8:1 region. That is about when the 400 and 305 were born. Low compression needed a longer stroke to make torque. That another reason the 283 and 327 dissappeared they couldn't put out the needed low speed torque. Read the Chevy Light Truck book by Moses Ludel. It has a whole section about making torque with low compression ratios. His recomendation use the motor with the longest stroke for its displacement. He then had RHS build a 8.7:1 383 for a 1976 chevy truck. The thing made like 400 ft/lbs of torque @ 2,500 rpm and 315 hp @ 5000. All from an iorn head 383 with a tiny comp cams 252H cam, it even had stock cast iorn manifolds, stock intake and carb, used stock 350 carb specs and timing specs.
Basically what I mean by this is that there is adequate proof that long stroke motors are less cam sensitive. If he was to change the valve springs to Z/28 spring (inexpensive @ most machine shops) that cam should run fine in a 305. I use a 204* & 214* duration cam with stock manifolds, 3.42;1 gears, and a 700r4 in my full size chevy van (4,500#). It cruises all day long @ 1,900 rpm but really goes when you mat it. It will climb some fairly steep grades in OD. It pull 5,000# trailers fine. The cam he is talking about is going in a F-body. It should be fine in daily driving after the spring issue is addressed.

five7kid

iTrader: (14)

I would suggest to all that we keep this to the originator's issues and questions. Go cyber-stroke your egos someplace else.

Vic, your last question: Stay with 1.5's. You're already close to the lift limit for the heads, no reason to stretch it.

I'd suggest you all read up on cam basics as well. Start here https://www.thirdgen.org/techbb2/sho...hreadid=229584 , and after you've purchased the rag and read the article about the dyno tests with varying lobe separation in particular, you should realize that there's more to cam technology than all of these blanket statements can possibly justify.

Again, Vic, about your cam: There's just too much unknown about it. I have found the Crane 2050 Compucam to be very versatile with my combo - smooth idle at 500 in drive, pulls hard from 3000 to 5500, will rev to 6300 w/o complaint. But, simply knowing ".454/.480, 216/228 @ .050", 112 LSA" is not enough to compare its performance and behavior with this cam you've got. There's just too much more to it.

Go ahead and install the cam and see how it does. Just make sure the valve train is up to it first.

Fast305

Thats what I was telling him. Make sure the springs can withstand the lift, then cam it. I would check with the cam manufacturer. Who would know better than them what the particular cam requires. NOBODY!!! My Z/28 springs were setup for .510" lift and cost less than $30.00 when I had my heads rebuilt. If you install that cam with the stock springs, you MUST check for coil bind or you could kill a pushrod or cam lobe.

My point was that there is much more to cam selection than simply cubic inch displacement.

Some of the things:

Intended RPM Range
Cruise RPM
Gearing
Transmission
Engine type
Heads
Intake & Induction
Computer Controlled?
Exhaust System
Compression Ratio
Vehicle Type
Vehicle Weight
Vehicle Usage
Other Things

That is why I said GET a cam recomendation from a cam company.

Heres Lazers Sheet

http://lazercams.com/camsub1.html

Comp, Crane, Isky, and almost all of the others have the same criteria. They sit there all day doing this stuff. That is why I said ASK them.

vic_V8

Thanks for all the help guys


thanks five7kid, I've read/messed with cams before, but never tried one this big in a 305, (put same cam in 383) I was looking to see if anyone did, Looks like I'll be the test mule

jfreeman74

I called CompCam today to get a recommendation from them and they gave me based on what I have in my sig that a 224/230 would be a good cam. I kind of think that is too big for a 305. I think the cam you have is on the mild side but it should work fine.

bnoon

jfreeman74, I can tell you that on a TPI 305, 224 duration on the intake side is a touch to much. I run a 224/224 .465/.465 cam in my '86 TPI 305 and it ran like crap on the stock programming. I had to set the idle to 750 in drive and remove 25% of fuel to about 3500, then remove 15% to 4000 before I had to add a bit of fuel on the top end. I also had to raise my lockup speed (when not in 4th) to eliminate surging at around 35 MPH.

vic_V8, with the shorter duration and a Holley you should be fine. The lift is good too as long as your porting is worth a darn on those 416's as those heads can be made to flow well up to .500 lift before stalling out. Do some searching on "porting 416" and you should find several hits with pictures under general engine tech and TPI forums.

jfreeman74

I have heard that having the duration the same for the intake and exhaust were not a good thing for the TPI's. Is that something that could have been a problem? What other mods do you have? Gears and stall have play a big part in what cam you choose. What heads did you use? I'm sure that I will need to do some programming in order to make it run perfect. Raising the idle is expected. 750 isn't that bad. My idle is higher than that now on my stock 202/206 cam.

Zepher, I like the sound of your car. It sounds like it could use a little tuning but overall sounds pretty good. Looks like is dumping a ton of fuel into the exhaust though. Was it doing that before the cam change?