I'm trying to get my hands on an L98 out of an '89 Trans Am. I am still trying to settle on what my setup will be if I can get the motor. Here is what it's looking like:

L98 w/ TBI (probably a 454 TB), Edelbrock Performer manifold, LT1 cam, aftermarket heads, Elgin 1.6 rockers, custom chip, dual snorkel air cleaner, Edelbrock headers & 3'' Flowmaster catback, Walboro 255lph fuel pump, 700R4 w/ mild shift kit, 3.23 or 3.42 posi rear

I plan on sticking with TBI and trying to make the best of it. Right now I am still undecided on my cylinder head choice. With this setup, about how much HP will I be making? Will there be any potential problems with this setup, and what should I do about my heads? Any feedback will be greatly appreciated.

 

What are you goals and what do you want from this motor?

I would probably give it a bit more cam, but depending on your application, that may not be the way to go.

You will also want to get good and friendly with the DIY PROM board, as you will be doing a bunch of tuning.

 

If I can run consistent times in the mid 13's that will be good enough for me. I still want to get halfway decent gas mileage, because I'll still be driving the car pretty often. This is why I'm considering 3.23's over 3.42's. My brother knows a guy who burnt a DIY chip for his car, and he did a great job. I don't have the time to learn how to burn my own chips, although I will definately consider learning sometime down the road.

 

Do you have time to play with your fuel pressure? If so,you can get a little fuel milage by leaning it as long as you have pressure gauge on the line at all times.Play with your timing too,should help as long as you don't go over board. Trial and error till you have time to learn to burn your own chips.

 

Timing and fuel pressure adjustments won't be a problem, and hopefully getting a good chip won't either.

I am reconsidering the 454TB, I will probably just keep my current TBI setup and go with 350 injectors. I am still undecided, however, on the cam and heads. Does anybody have input on what heads would be best? Should I keep my L98 heads and get them ported, or buy some aftermarket heads?

 

if you want a 13 sec quarter mile your going to need a better cam and possibly better heads if your not willing to do a full port job.

Maybe some dart iron eagle heads or vortecs, they are affordable and nice sets, you will need a cam a bit bigger than that to run 13s though....

Maybe think of a cam like from comp cams xe line (262 or 268 would be good but, probably much tougher to tune than a lt1 cam would).

Best advise i could give you if you want to stay that mild is, lower your expectations just a little (no offense). Then again your setup with a fine tuned suspension and a slight stall could probably net you a high 13 possibly but, most likely low 14s.

Btw go with a 454 tb or holley 670 tb and use 454 or the police injecters would be my advice from what i've heard.

That and don't use a performer intake manifold, at least use a performer rpm, or performer airgap or rpm air gap. Weiand stealth would be a good choice too (what i'm going with).

If you use the carb manifolds you will need a tb adapter but, i'd be willing to bet the better manifolds are worth the extra couple bucks buying an adapter