I have a freshened 30 over L98 still with dish top stock type replacement pistons, and freshened but stock iron L98 heads. I have two cams on the shelf at home for this budget build - a .447/.459 117 LSA 1996-97 LT1 cam, and the .474/.510" ZZ4 cam. I was originally going to use the ZZ4 cam but after looking into how I will have to grind or cut the guides/retainers for clearance and how running stock press in studs is not a good idea, I am thinking about using the smaller LT1 cam.

Someone told me that the 117 LSA LT1 cam won't run well in a gen 1 headed engine - can any confirm or disprove this? Anyone who has personally run an LT1 cam in a stock L98?

THanks

Steve

 

What I did with my L98 was put 1.6 rockers on it, which makes the cam from .415/.430 lift to .443/.459 and I believe that helped a good deal.

I never got to fully tune that setup. I believe I dyno'd 246whp with the bolt ons with a mid 12's to 1 air fuel ratio. After pulleys and 1.6 rockers, I dyno'd 254whp with around 14.2 to 1 air fuel. It leaned out tremendously but I cant remember if altered any fuel or timing with those mods. I want to say i did pull out a bit of fuel but certainly not much to make that much of a drop in air fuel ratio on that dyno.
I forget the exact track times, but I believe in good air weather, I ran 13.2's at 101.x mph. With 1.6 rockers and abit better air quality, it went 12.95 at 103.8. Some of that gain was air quality alone, but some was definately due to increased cam lift.

L98 cam I believe is around 207/213 at .050" and 115lsa.

I dont see how a LT1 cam would be any better or worse than a 1.6 rocker L98 cam. It should work just fine although not the best choice. L98 may have more duration but not sure of how aggressive the ramp rates are.

ZZ4 would make most power out of all of them I think, but the lift issue is a concern. If you dont want the risk, then Lt1 isnt a bad idea.

Is an aftermarket cam out of the budget on this one? You can get a cheater type cam spec'd up with lift limit but more aggressive lobes and a tighter LSA to make more power than all 3 cams.

 

Ive run a .510 lift cam with stock L98 heads with no machining. We just threw it together to see how it would work. No one had told us it wouldnt. Lol. Had to have springs of course. The cam was an SLP part for "extensively modified TPI". IIRC it was 224/230@.050 .503/.510. 112 LSA.

With porting of the heads, ported factory base and plenum, stock runners, it ran strong. Would have been better with some ECM tuning. We just used an AFPR and set pressure at 55psi. This was on an 87 GTA 5.7 MAF car BTW.

 

The LT1 cam will work better than the L98. It's a slightly bigger cam than the L98. With just a full exhaust system my car made 257rwhp on the dyno. Oh by the way, My car is a 1990 5.7 G92.

 

Thanks guys, yeah buying a cam is out of the question, this is my 5th car I'm working on and although I don't want to completely half *** anything, it is a low priority so I'd like to use up whatever good spare parts I have kicking around my basement. Orr89, running 12's with similar specs through the 1.6 rockers is very good info, that is way faster than this thing would run anyway I'm sure. The reason I was worried about the ZZ4 cam is that this engine WAS run byt the previous owner with the ZZ4 cam with no work done to improve clearances or anything, and the valve guides were WRECKED and I am in the process of re-doing them right now (the guides were ovals, so badly you could see it w/ the naked eye. I'm talking about 10 thousandths guide to stem clearance on some of the exhaust valves, holy crap.) Although I will probably never put more than a few thousand miles on this thing I don't want to set it up for breakage either. Sounds like the LT1 cam might be the way to go. I have the .503/.510" comp roller cam in my other 350 but that has aftermarket heads so I didn't have to wory about clearance or screw in studs or guide plates since that was all set out of the box.

Thanks

Steve