Hi im new to the site and i have a 1988 iroc-z l98 tpi and have been wanting to start a performance build on this car for some time now but i seem to be having a hard time finding any useful (if any at all) technical info on the ins and outs of building an l98. I dont want to swap it out-just build what i have to its highest potential w/o sacraficing reliability or having it blow sky high. Minding that this will be driven on the street, does anyone know of a typical hp/tq ceiling that an l98 can run w/o putting it at serious risk of major damage or anything truely useful about a performance build or where i can get the info?

 

search. there is more on this site about what your asking than you ever want to know.

 

you can run a good heads/cam/intake setup on the stock shortblock and keep it fairly reliable. Depending on compression ratio, which will probly only be in the mid 9's to 1, you can get probly 400hp on motor and be somewhat street safe friendly and not having to rev it up to the moon.

Keeping TPI will limit your build, to somewhere around 300-330whp i'd say on a fully ported TPI setup. STOCK TPI would be near 300whp i'd say

 

Right. We just dyno'd one with a stock block sans the cam and a 700R4 tranny. Had AFR heads and a good exhaust system. SLP runners and Edelbrock intake manifold. Dyno'd 321rwhp on a stingy dyno. By the way the car is California smog legal.

I feel the car will make 330rwhp with no problem. By the way he was running the Comp XFI268 cam. He should be well into the 12 second bracket in the quarter mile.

With a few mods here and there I believe a 350rwhp car is very doable with the stock short block. If the motor had an M6 we would be talking around the 375rwhp mark.

 

any cam sheet numbers on the cam, web site only says good low and mid.

likely a 268 @ .006 dur.

1.6 rr ??

found it

cam lift is with 1.6

Hyd. 1800 to 5800 08-466-8 268XFI HR13 268 276 218 224 .570 .565 113°

 

Well i guess what i really meant was I want to keep the same block i've got and keep it tpi and all, but other than that, sky's the limit. I just didn't want to swap in an entirely different motor or anything. It's going to be a heavily modified car (internals, blueprinted, maybe forced ind.?, etc) but i dont see too much info on that around usually- people usually just say make it a 383 or put in an ls1 or something. I'm hoping for something well over 300hp i just wondered how much the block i've got could take w/ being thin-wall casted iron block from an 80's iroc using tpi.

 

As has been said many times the heads are the key to power. Right now the AFR Eliminator heads are at the top of the heap. The Dart Pro One Platinums are supposed to be as good but I have not personally seen any results. So get the best heads you can and go from there. You will need aftermarket TPI parts such as the Edelbrock intake manifold and bigger runners.