five7kid

iTrader: (14)

Not sure why nobody mentioned this, but stock Vortec heads can't handle more than about .450" lift, even with better springs, unless you cut the tops of the guides or use beehive springs/retainers.

If you're looking for better track ET/MPH and aren't worried about how it drives on the street, with everything else in place a 750 CFM carb will be quicker/faster than a 650 CFM, all else being equal. If you are running a carb, you should consider either a dyno tune session, or get a wideband O2 system.

GreggymacZ28

I guess should have been more careful with my words. I was not stating that i was getting a 100% volumetric efficiency, i was showing how that changed the game from what would have been a 575cfm to a 748 at a 100% volumetric efficiency, ill punch the real numbers so you can see where its at for me.

355x5600=1,988,000/3456=575(or 100% volumetric efficiency), ok now lets lower it to 85% so 575x.85=489 then take that 489 and multiply it by a 1.4 and you get...685, but then take that its a 1.5 as yuo can multiply anywhere between 1.2-1.5, and at 1.5 you get a 734. I'd rather buy bigger and down jet it, than having my carb not have enough cfm's and have to get a new one.

Diggler: Yeah i know what you mean,ha. It's winter so it gives me more play time, but if it was summer i definitely would not want to have to tune it. I would love to just set it on the motor as well

GreggymacZ28

Someone has stated some numbers on that area, but not what you posted, i know that Fast 383 said, "Your Vortec heads work around .525 lift." Which was right around what i was thinking also.

But yeah a wideband is what im looking at to get, i just dont have the money to dish out on it now, if i could find a cheaper one though, I'd be all over it

five7kid

iTrader: (14)

.525" lift only with beehive springs, unless the guides have been cut.

Ron_90

Or you can grind the retainers 3/32 of an inch and install new valvesprings. Costs a lot less than beehive springs and gives you slightly more clearance

http://www.nastyz28.com/forum/showthread.php?t=56505 (NastyZ28 guide to vortec heads)

@DIGGLER
Check out my build after it's finished and tell me TBI sucks again

DIGGLER

iTrader: (1)

no need to wait, TBI sucks. good for stockish stuff as a better driving setup than a carb, but for anything performance oriented, it sucks.
why spend $700 on a TBI setup when you could spend just a little more on a vic.jr efi intake, tb, and megasquirt?

Ron_90

Because it came with my car and I got a great deal on the new ECM and the other stuff. All in all, I have less than $300 in my EFI setup. It sucks if it isn't tuned, but when tuned it'll beat a carb on the same engine any time of the day.

xpndbl3

iTrader: (5)

Ron_90

Ok, ok there are better systems to be had for that kind of money, but if you can get everything for cheap or free TBI isn't a half-bad way to go

GreggymacZ28

Thats good info. Are there any beehive springs that are rather cheap on summit? It seems they range from 60-400? I'm lost on where to begin with those.

84firebird383

I know a guy that ran a vortec headed 383 in an 85 camaro with a .450 lift rule hydraulic cam and ran mid to low 11's @ 118mph with 3.42 gears. It did have a 2700 lb race weight though.

GreggymacZ28

wow thats really good, but my weights around 3500-3600, but that gives me hope if i do extend my heads lift a little more and get a .525 lift.

84firebird383

I'm not sure what he all had to do to the heads but he now has a solid flat tappet in it and running 10.8's @123 mph.

GreggymacZ28

Thats alot faster than what i want to go,ha. But that sounds really good for a .450 lift, he mightve done something different to run that?

84firebird383

The solid cam has more lift. I'm not sure what he did to his heads to run the solid cam. The motor itself is a budget 383 built by my friend that works at Competition Products. He was amazed himself at how fast the car went, but it is mostly due to the weight reduction. In a 3600 lb car it would most likely be quite a bit slower.

GreggymacZ28

Yeah, that is very true. If we had the exact same setup in the performance area, if you take a tenth for every 100 pounds then if he was running 11.50, I'd be running 12.40. The weight reduction is a major factor, but not something im really looking to do for a street/strip car.

GreggymacZ28

Ok so i finally purchased a carburetor, it's a 4150 holley 750 double pumper with mechanical secondaries, and the PO had the primary jets were #73 and the secondaries were #80 and then the power valve has the "picture window" holes and i think is #65 or a 6.5". These sound like pretty good numbers for a race carb to start with, i'll be putting it on soon to see how it runs.

Also, does anyone know how much valve reliefs run at a machine shop? Would beehive springs be less money?

Ron_90

Not sure if you read over my earlier post but there's great, cheap way to make your current setup work up to .540" lift. Just grind the stock retainers and all you need is new valvesprings that will fit Vortec heads ($40-80). Over half the price of beehives (which you have to buy new retainers for if I'm not mistaken)

GreggymacZ28

Oh i did read that, i just forgot about it, alright that looks good, im going to read up on it more to see if its something i can do, i dont want to get myself into anything that ill end up messing up

GreggymacZ28

So let me see if i have this right, what that's saying is all i have to do is grind off approximately 3/32" off the bottoms of the stock Vortec retainers with a grinder and i will have improved my lift from .450 to .550?

Ron_90

That would be correct.

.093 (3/32) +.450= .543

I'll be doing this myself when my Vortec (305) heads come in. It should work, as that thread has been much referenced in other forums as well and I've read multiple accounts of people doing it without a problem

GreggymacZ28

Hmm...seems simple enough, thanks! And yeah ive noticed that they showed in that thread alot of people who have done this and it seems noone has any complaints, i was just making sure that theres nothing else i also have to do. So just to clarify, grinding the retainers and that alone will bring my lift to .550? sorry for the same question just making sure im not missing that there is something else i also have to do.

Ron_90

From what I've gathered, yup that's it I did a bunch of research on how I was gonna make my Vortec heads work on a budget before I decided to get them. Hell, I'd do it myself and confirm for you if I had my heads and was running anywhere near that amount of lift lol

By the way, what cam did you get?

GreggymacZ28

Alright thats perfect. And i have not gotten a cam yet, as i was waiting to see if i was going to be able to expand my lift on my heads, but now that i know this if i can do it successfully this is the cam i am looking at...

http://www.summitracing.com/parts/CCA-08-433-8/

pancherj

Cam selection looks pretty good. I would rather see it on a 108LSA. That is similar to what I have in my 350. I don't know if the stock vortecs will flow enough to support the horespower you need for 12.0's. I have ported AFR's and 10.2:1 compression with a 3600 stall converter. I am shifting at 700RPM. My car is about 200lbs lighter than yours. I generally run 11.80-12.00 (depending on the weather).

Orr89RocZ

iTrader: (20)

As others have said, for 11's you need to cam up, stall up, gear up, suspension work, sticky tires, and it should get close.....

10.5 to 1 with iron heads is strong...does it run on 93 pump gas well? How much timing you have?

That compression will work well with the cam just measure your lift capacity on the head after you make those modifications. beehives may get you .510-.520" lift + alittle retainer grinding but its gonna be pushing it. Definately measure your clearance on EACH valve to make sure you have enough. Last thing you need is to have it bind, break spring and drop valve into the motor.

Stall, i'd go as high as 4000. 3600-4000 on a big cam 350 is needed to get it off the line. No torque like a 383. 3.73 gear should match well enough. Performer RPM or vic jr single plane for vortecs can work ok. 750 carb should work well, I had a friend who used that on a Lt1 cammed vortec 355 budget motor and it ran better with it than the old 600-650 cfm carb. I dont know **** about carbs tho.

My buddy's 3400lb 86 iroc went 12.2's in warmer air at 112 mph with a 350 with old AFR 190 heads and 280xfi roller cam. It was only a 330whp combo and had somewhere in the 1.70 range 60 foot with a 3600 stall. Car lacked compression to really shine with that big cam, and 3600 stall wasnt quite enough. 230+ deg duration on a 350 likes closer to 4000 stall IMO.

Vortec heads should make 330whp once well tuned. With the lack of head flow, you need to cam up and compression up to make up for it.

GreggymacZ28

I actually found the paper i had written notes on from the guy i bought the motor from and i scribbled something about the valve guide, so he might have actually grinded it some, i might give him a call soon. And a stall upgrade is basically the only thing you mentioned that im not doing yet, but it definitely is a possiblity. But if i can get that cam to run fine in my heads, and i can get my slicks and tune my carb right i am basically hoping for 12.20's to begin with. Then maybe some suspension or stall upgrades when the time is right to put me into the 11's?

xpndbl3

iTrader: (5)

do the stall long before the cam, otherwise it'll be a dog out of the gate.

Orr89RocZ

iTrader: (20)

possibly. Like others have said, you need to trap around 112 in a very efficient setup to get 11's. Else figure 114+ mph for a so-so suspension launch setup with less than optimal gearing/etc.

5-7 mph is a good bit of hp from where you are at now. Abit more cam will gain half that I'm sure. Well tuned carb quite possibly can get most of the rest if not all. Some may be found in a more efficient converter but kinda unlikely. Some in improved suspension performance but again, thats abit unlikely. Those two things pick up ET rather than MPH.

Still should get 12.2's even if you only pick up 3-4mph. I run 12.2's at 110 in my 99 trans am with a 1.67 60 foot and its far from optimized. I was hoping for 11's with it with better tune, more suspension work, and more converter.

DeltaElite121

Don't underestimate the importance of a good converter. A strong motor makes little difference if the rest of your car can't do anything with the power. Obviously, work within your means.. but definitely don't skimp on the converter if that's what you're thinking about doing. It makes a huge difference.

GreggymacZ28

I have a 2500 stall now, what are you guys with like 3600+ stalls able to rev your engine up rpm wise before take off? I'm at about 2400 on mine before the green. Also, yeah i'm definitely not going to "skimp" on anything im not trying to do that, just trying to see where i get my gains. If it's not running as well as it should with a new cam and carb then ill put a stall in and see where my gains are there, and then if my 60' is bad, then ill go to suspension and see where i get my gains then. I like to know where i gained most of my power.

GreggymacZ28

Sounds like what youre running is exactly what i want

3rd gen Will

iTrader: (8)

IMO, a 230/236 is to much cam and will make your car slower than if you ran something in 220/230 range. you will lose lower end power and you won't net much if anything up top over due the flow capability of the vortec heads. stock they max out at around .500 lift and flow approx 240 cfm. There isn't much reason to go past 6000rpm with your Performer RPM intake manifold either. Id run something like this in your combo, make good power for drag racing and still be streetable.

http://www.summitracing.com/parts/CCA-08-423-8/

Orr89RocZ

iTrader: (20)

My 3200 i can get to about 2200-2400 depending. My old 3600 I got to about 2600 I think. My 4000-4200 ish stall I can get to 3100 if the brakes hold it.

GreggymacZ28

So my 2500 is getting a very decent amount then

Orr89RocZ

iTrader: (20)

yeah doesnt seem right. when stopped at idle, if you mash the gas, what does the rpms flash to before the car seems to get moving or spinning tire?

GreggymacZ28

What you say makes sense, and was right along the lines of the cam i stated earlier, my ht383 cam now has a 196/207 duration so a 224/230 seems to be a considerable jump. Also the lift is touching .510 which is close to what the other one was running.

GreggymacZ28

You know what i never noticed that, everytime i watched the rpms it was a little after i smashed the gas as i'd be watching the light and then itd take me a bit to look down so i know my numbers there wont be accurate.

GreggymacZ28

I'm hearing mixed reviews on the cam selection, is the duration on this one...
http://www.summitracing.com/parts/CCA-08-433-8/
too big?

Is this cam actually better?
http://www.summitracing.com/parts/CCA-08-423-8/

xpndbl3

iTrader: (5)

i was in the 240s duration with my old vortec headed combo FYI, you can't go "too big" just pick the RPM range you want it to work in. We had a light car combo running a much much bigger solid roller back in the day with those heads ported up.

GreggymacZ28

Ok exactly! thank you, i didnt think that cam was too big. And it works right in the rpm range i need!

Orr89RocZ

iTrader: (20)

Thats the biggest I'd run for now....its not small but not huge. I think it will work ok.

GreggymacZ28

Yeah thats what i was thinking, the valve springs im getting are good up to .550" so i think .525" should be a pretty safe run. Ill check the R-G clearance to make sure.

Orr89RocZ

iTrader: (20)

Remember if you need abit more clearance, you can also add .050" of shim under the valvesprings, and run a + .050 offset lock to raise retainer height the same. This shifts the entire spring package up .050". May need lash caps tho since your valvestems will be closer to being flush with the retainer. Rocker arms may contact retainer this way. So you'd have to find a retainer with .050" offset and designed for use with lash caps. They do exist I just dont know the part numbers.

3rd gen Will

iTrader: (8)

If there is no going "too big" why not just throw a 250 duration cam in there then!

Your combo of the vortec's w/ a 240 likely worked because of the porting and a lighter car, probably had a high stall/small converter and 4.11 gear or better also. He has a stock weight third gen with stock vortecs and a 2500 stall, probably a heavy 13" converter, and 3.73's. You need low end power to get a 3500+lb car out of the hole and moving. That cam does not line up with his combo what so ever.

Absolutely no way I'd run a 236/242 with stock vortecs. I wouldn't even run a cam that big with my AFR's.

gtpro700

Hmmmm that's what she said lol

Orr89RocZ

iTrader: (20)

He will be changing the converter to match and 3.73's will be plenty. With a cam that big, you have to gear up and stall high to make it all work. Thats what stock eliminator guys do. gear and rpm!

xpndbl3

iTrader: (5)

haha Orr, and that's why some of us are over half a second faster than the rest of them, for building a matched combo that makes power.

3rd gen Will

iTrader: (8)

wait, you call stock vortecs and a 240 cam a matched combo?

Orr89RocZ

iTrader: (20)

To squeeze the most out of the heads which are a restriction you need MORE cam to overcome the lack of port. Remember he is trying for 11's with vortecs...thats not an easy task. Cam that big on small heads certainly isnt the best way to do it, but thats what he has and thats what its gonna take to make it happen. Now you just need to get a high stall speed converter and gear/tire to work in the high rpms that motor needs to turn to make power. 240 cam and stock vortecs isnt matched by itself...you need compression, gear, stall, suspension and tune to make it all accomplish the task at hand.

It be better to have a good head like a AFR or whoever with 195-210 cc runners and 300cfm. Then you can use a 224 cam and possibly get 11's. Less gear less converter...but it is what it is

Its like the cam only LS1 guys running bottom 10's high 9's in race cars. LOADS of gear, 5000 stall or higher in some, huge 240 deg hyd rollers on stock heads. The cams are way big for the heads but its how you force them to make power to run those ET's.