I will be getting the Stealth Ram shortly, but in the mean time I would like to do a cam swap. Currently I have a 1989 L98. I do NOT want to remove the heads at all at this time. So what is the largest cam I can run that will idle with a little bit of lope but will not require any machining of the heads at all. I also need it to be able to work with the stock computer that has the ARAP PROM. I understand that I will need to change the springs. I want a cam that will cost around $200 and take advantage of the StealthRam and my other mods which include:
SLP 1 3/4 headers
No cat
Hooker Catback
Nolley StealthRam
ARAP prom
and MSD ignition

Remember that I need it to be cheap and work with the stock heads without machining.

 

You might be able to get away with the LT4 HOT w/ 1.5 Rockers, to keep lift off the valve guides

Match that up with some Comp 981 springs or the Gm LT4 valve springs.

The cam has a fairly Tame Duration @ .5, So it sould work O-K with your ARAP bin w/ Mass Air.

Do you burn your own PROM's ? I wouldnt really advise a cam swap without it. while it may run O-K, It will run much better with some Tunercat TLC

Much less a Cam swap w/ HSR... your getting into a radically differant thatn stock setup there

 

You really should do something with the heads. A stealth ram with the hotcam will work but not too well with the stock heads.

Bob

 

Springs arnt the only thing to worry about. Ive seen people put cams in with lift within the limit of the stock springs and the people have had their pressed in studs fly out.

 

What are the specs on the LT4 HOT CAM with the 1.5 rockers? Will it be safe with the press in studs and stock sized vlave guides? I will only be reving it till about 5300RPMs, thats where the trans shifts. That would work out great if it will fit, then when I do get new heads I can just slap a set of 1.6 ratio rocker arms on it and be set. I am waiting on buying a programmer an software right now because I want to get heads eventually. Anyother comments. Remember I dont wanna blow up the motor and I heard that its not safe to run over .480 lift on bone stock heads with new springs.

 

The concern with Running over .480 lift on stock heads is that the retainer Hits the Valve guide. Thats not a very good thing

the LT4 HOT is .525 w/ 1.6 Rockers, so do your math there. I think it puts you pretty close to the .480 point.

I woudl think the press in studs would be just fine. Were not talking super high Spring rates here.

Altho, If I were you I would buy thing Computer stuff NOW and leave the cam and heads Untill later.

Your goin to need to start writing your own to get that HSR to work right.

Your going to have to disable the egr at the least.

 

If you're gonna be putting that much work into the engine, at least pull the heads and have 'em gone over. Put in the screw in studs, a good valve job, and machine down the guides to clear some more lift at the very least. With the engine apart anyway it's not that much extra work, and the little stuff isn't that expensive. But your heads are really gonna hurt you with the Stealth ram and a decent cam, so either take some time and give 'em a good porting, or step up to a better set. Check this thread.
https://www.thirdgen.org/techbb2/sho...n+head+project

 

If youre using the stock unported heads, I wouldnt use the hot cam. Maybe the LT4 or ZZ4 cam would be better. Not sure if you can get that for peanuts though.

 

Isnt the LT4 and Hot Cam the same?

 

I thought I heard that there is 2 versions of it. The regular LT4 cam and a hotcam.

Bob

 

.525 / 1.6 = .328125

.32815 * 1.5 = .4921875

So valve lift for the LT4 Hot Cam utilizing 1.5:1 rockers is approximately .492" (Intake and Exhaust).

And yes, most people will agree that the retainers get too close for comfort above about .480" lift on stock heads and with the high intensity roller lobes requiring a fairly stout valve spring, the press in studs are also a no-no with any high-er performance camshaft.

 

Matt87GTA what thickness head gaskets are you using with the 23* heads? I wanted to get the CNC ported ones but I heard that the porting brings the cc up to 66. I wanted to use a thinner head gasket to bring it back down to 64. I heard that TPIS has on that is .029 in thick....what wil this affect????

 

The biggest cam I recommend for stock heads is the Compucam 2032. Anything over .470-.480" lift will more than likely have problems with the retainers hitting the valve guides. That includes the ZZ4 and LT4 HOT cam. The stock LT4 cam isnt worth the swap.