I know Z28 springs can handle up to .480 lift and the Comp 268XE cam is right there. But thing is I don't a Z28 motor anymore, I have the GM Goodwrench. It has 1.94/1.5 heads if that helps.

 

the name z28 springs are because they were in the lt-1 motor in '70. they will fit your heads. but why not just get the comp cam ones for that cam?

 

What I mean is I don't want to change the springs, I want to keep the ones that came with this motor.

 

I think you might have to do a little bit of spring work to make that cam happy. When you look up the cam on Comp's site it should tell you if you need different than stock springs. The XE268 has lift in the region of .470, if I recall correctly. That would dictate a bit stronger than stock set of springs. You might even have to do some machining to lower the seats and fit in a taller spring.

Not what you want to hear, so I hope it isn't necessary.

But check with Comp, they have a 1-800 number on their webpage.

 

OK, I looked it up for you. Go to this page and look at part number 981.

http://www.compcams.com/catalog/302.html

It is somewhat stronger than the stock springs, I believe.

 

The GM Z28 springs PN 3927142 Fit the requirements for that cam. They may need the Installed height checked/ adjusted
for best setup. They are rated for .480 lift cams if when installed
at 1.70" closed installed height and have 110/120lbs. seat pressure.
This is more than enough and safe with 1.5 rockers
with .060 extra spring clearence at full lift. If you're really worried about it. you can remove the spring shield (.030" thick)
which will increase your installed height to 1.73" or more,
and only drop your seat spring pressure about 5 lbs.
Now the spring is good for an extra .030" lift, opening your saftey
margin to .090". Remember the originally application for that spring was the 69 Z28 "140 off road cam" with .494/.512 lift. gross. And a lot more RPM.... You could even slip on some 1.6 ratio rockers on the intake side only( most motors don't like 1.6 exhausts anyways) if you removed the oil shields and still have .060" clearance with your new gross intake lift (.5088")
Now I'm giving away secrets...

These springs are hard to beat, when used in the correct application.

 

How hard and how much work is involved changing springs. This sucks, I don't have a lot of money right now, I'm only changing the cam cause I feel like it's the best time to do it, since I have a valve cover and intake gasket leak.

 

It is'nt hard just a PITA!!! Your legs and lower back are gonna hate you later that day.

 

over 7500 post and you don't know if you need springs or not and you don't know what's involved in changing them? damn what do you post about?

 

The Z28 springs are cheap, I think about $25.

 

I know I know. Unfortunately I'm not very mechanically inclined, plus I haven't had the oppurtunity to work on cars like most of you. I don't have the work area or tools, not too mention the IROC was my only car at the time so I couldn't experiment. I was young and not interested in the cars when my brother had a garage and built many engines, too bad I didn't take the time to help him.

 

Mark,,,, Mark MARK!!! Read my post!!!

If you got the GM Z28 springs already, You're ok.

What springs are on your motor ,,, right now?

 

I'm not sure, I've got the GM Goodwrench 350, I don't know what springs. But RB83L69 strongly advised me to get springs, and I hate to go against what he said. I dont' want to risk anything.

Here's all the info I have on the engine.
Horsepower¹:
249 HP @ 5,000 RPM
Torque¹:
304 FT/LBS @ 3,500 RPM

Redline:
5,200 RPM
Comp. Ratio:
8.50:1

Heads:
Cast Iron, 72 cc
Valves:
1.940" I, 1.500" E

Camshaft Lift:
Hydraulic; 0.390" I , 0.410" E
Duration @ 0.050":
195° I, 202° E

Block:
4 Bolt Main, 2 Piece Rear Main Seal, 4.000" Bore

Crankshaft:
Cast Iron Nodular, 3.480" Stroke

 

I see, You have a Stock Goodwrench crate motor. Thses motor
do not come with the Z28 spring I mentioned.
The springs on your motor can handle the lift of your new cam, but DO NOT have enough spring pressure to control
the valvetrain at high rpm.

The GM Z28 springs PN 3927142 would do nicely for this cam.
But so would the Comp cams 981 spring. So go with the Comp spring.

Your motor only has 8.5:1 cr so your new cam will
not give the results you are lookin for.
Your cr should be 9.5 to 10.0:1 to match your new cam.
You could kill two birds with one stone here, by removing your heads and having them flat milled .060" to raise the compression ratio and install your new springs while you're at it.
Be sure to get Felpro thin .015" shim head gaskets to help maximize compression with what you have. Your new cr should be
9.31:1. Much better. Call a local comptent automotive machine shop for an estimate. This is routine stuff for them.
You could also do a basic home pocket port job
while the heads are off.
These things combined, will really give you the effect you're
looking for with your new cam swap. I know this involves more money and work, but it will be well worth it.
Check the head casting # on your heads. They should be 993.
These heads will port up pretty good with a few nights work and a die grinder. May be your brother could help you with this.
Good Luck

 

Yeah, money is tight right now, I'm pushing it to buy the cam. But I figure I should see a nice gain from this 390/410 lift cam, I hope for low 14s with the cam. After head work and TC low 13s.

 

It's only money, you'll get more..... old saying

I'd delay the cam swap till I could collect up the money to do it right. You'll be farther ahead in the long run.

 

Well, I think I can get the Comp Springs along with the cam, just I won't be able to up the compression for now. Next summer though. I have to fix this intake/valve cover leak so I'm going to go ahead with the swap. I'll post G-Tech results of the improvement some time later too.

 

No money....then how the hell did you get that smashing $45,000 'vette..

 

That's my future father in laws. He plans on selling/trading it in to get an '03.