I know I've asked a number of stupid questions which have probably been asked to death......so here's another...

L98 heads. How do they flow. If I decide to go with LPE intake and Headers will the stock heads be a serious choke point and hurt overall performance?

 

as stock castings they suck! u will need an aftermarket head, or the 113's ported.

 

What year is your car?

85/86E heads suck pretty bad.
86L/87 heads are good for 300ish HP unported.
88-91 heads are good for 350ish HP unported.

 

It's a 90. Sorry. So the heads should not be a choke point. I perfer not to change the heads because keeping the car original is a concern. I really don't want to mess with the heads if I don't have to.

But if the heads prevent the intake and headers from being useful, than there's no use doing the other mods.

 

thought u had an early L-98, so scorp is right!

i myselve just bought the trickflow heads. i figured it was well worth the money.

 

sent u a message brian, could u reply.

 

It really depends on what you're after. If you go with a full superram intake and a new cam then yeah they'll be a choke point. You'll still get much better results than the stock setup, but it won't be everything you could get.

 

Since you have a 90... the heads you have should be alright unported... but there are several things to consider before you lay a wrench to your car.

1. your realistic budget
2. what do you want to achieve immediately
3. what are your long term goals
4. whatever mods you make... what other mods need to accompany to ensure safety... ie... 1000hp motor needs a stronger trans, better suspension and probably a stronger rear end.

I mention this because if you go through the trouble of taking the intake off the motor, it is only a few more simple steps to remove the heads for porting or replacement. Since you are already there, what about a new cam or headers? It makes more sense to dissassemble it once and do it all. However, budget and short term\long term goals play on this heavily.

One more point... I made the mistake of buying a moster cam for a Pontiac 400 once. I don't remember the specs, but I had a stock motor at the time. In order to best utilize the cam, I would have needed gaint headers, at least 10.1 compression, high flow heads, stall converter, 4.11 gears, and a whole host of crap that I couldn't afford... all for one mod. (I realize a cam may not be the best example), but I hope you get my point.

 

What do I want. Well, I'd like a little noise from the headers, a little low-mid punch from the intake.

However, I don't want to do the work if I'm pissing in the wind.

As noted in another thread, and I completely agree, the motor has to be CONSISTENT throughout the build. Is the fuel system up to par, etc....

So I consider these upgrades minor. I guess what I am trying to figure out is that will I be 80% efficient if this is all I do? Without the heads and without the cam. Will I be leaving 20% on the table for not making those changes? Will I be leaving 70% on the table?

If I can get between 80-90% of the benefit from the intake/header swap. I can live with that. If down the line I determine to sqeeze every drop of power I can still add a cam and heads, right? Then the drivetrain and everything else becomes an issue.

Will these upgrades be a waste of time?

 

Thanks, that's my point. I already did this with a C3. I started changing the cam, ended up doing everything but the short block. I don't want to get into "while I'm here" syndrome. It's expensive.

I am looking at intake and headers. That's it. I MAY go as far as 1.6 rockers, but that is a streach. If the heads are REALLY holding me back, then I may not do anything.

 

From your description I suggest you install an Accel base with AS&M LT runners, do exhaust (LT headers, hi-flow cat & cat-back), pulleys, 1.6:1 RRs, cut lid with K&N, AFPR.

Check out Vic'89's mods; with stock heads & cam, above intake mods and 3.07 gears and an A4 he runs mid-high 12s in the 1/4 mile and dynos at around 325-335chp.

Your stock #113 heads will flow to ~350chp; ported to >400chp.

The intake mods suggested here will maintain low end, enhance mid & upper RPM torque and look stock.

 

how about SLP siamese runners instead of ASM with that combo???

 

You mentioned that you wanted to keep the car as original as possible, but also wanted more power. Well, the heads on a 1990 are good as is for around 350 HP, as has been noted. But if you do decide to modify the inner workings of the car for even more power than the 350 mentioned earlier, port the heads. They'll still be original, only better.

 

That's EXACTLY what I want!!!



I have the cat back. Now I just have to convince myself to take a wrench to a perfectly good working car.....

I ran to the local engine builder here, a guy with a good reputation, he says the heads are OK. He also said he can give me a chip, a GM chip, that is re-programmed. but warned me repeatedly, it's for the "track only" so I can't use it on the street.

Seems like Ski-it-down is the chip expert here, I'll check with him when the time comes.

65ZO1, you live pretty close, doing anything this winter? No smoking in the garage though.

 

I have a set of ported '88 L-98 heads with about 5k miles on them. If your interested in details, let me know.

Gary
Kwik88