Martin Steel

Who owns the most powerful normally aspirated L98 on Thirdgen.org?
I was curious about the hp limits of the motor and what combination will get me there.

I searched my back issues but magazine articles rarely discuss the L98.I did however, learn that 346ci LS1s max at about 430hp at the wheels with bolt ons plus heads and cam and a bit over 500 RWHP when rebuilt w/ max cubes (422ci).

That leads me to another question. How much would that killer L98 cost to build?
The heads, cam, and bolt ons for an LS1 would probably not exceed $6000

PLEASE SKIP TO POST #6 FOR REVISIONS TO THE PRECEEDING QUESTION AND TO CONTINUE THIS DISCUSSION.
Thank you

rezinn

Define "L98." There are lots of people with 383s making those numbers with a miniram, a huge cam, and good heads. Probably some 350s close to that as well. Any with the stock intake, like the LS1 retains? Not likely.

Martin Steel

For this discussion I would consider an L98 to be any motor retaining the original block.
Any cubic inches or intake is fair play. I am mostly interested in the cost of the rotating assembly and machine work/labor for a 396 or 406 for example.

ME Leigh

All your really asking is who has the most power from a 350 block, theres nothing special about a L98 block that makes more power or anything.

TransamGTA350

iTrader: (2)

Probably a better question to ask would be:

Who has the most powerful, naturally aspirated, TPI setup?

Otherwise, it's just any other chevy small block with the same potential as any LS1, LT1, or carb setup. If you want to say that it's an L98, then it needs to have the TPI setup.

Martin Steel

I am sorry for not defining my use of “L98” more carefully. I really just want to learn more about the maximum hp potential of motors that began originally installed as an L98. So I guess it would be acceptable to discuss anyone’s motor that began as a 1st gen. Chevy 350. The only stipulations remaining are that it still uses some form of fuel injection and is normally aspirated. Everything else is fair game, displacement change, custom sheet metal manifold, upgraded internals, weld on 4 more cylinders, whatever.

There has to be a lot of you that can help. Please describe your combination and include HP (preferably rear wheel) and a cost breakdown.

Thanks

ME Leigh

The horsepower capability of an LL98 block is the same as any other 350 block. A block is pretty much just a block, no major difference, and it doesn't matter.

Martin Steel

ME Leigh
I agreed, prior to your recent post, to discuss all first gen. Chevy 350s. Certainly you are not suggesting that all motors of the same displacement produce near identical horsepower and torque. I would suggest that block design and even the material from which it is constructed would influence the outcome. The LS1 for example is a different design making it impossible to bolt on its superior heads and intake.
I could continue, but I rather not argue about engine blocks and maintain focus on my question. We are after all at thirdgen.org. I assumed that many here would have rebuilt the L98s in their IROC or GTA.

Kingtal0n

<b>maximum hp potential of motors that began originally installed as an L98.</b>

thats so ambiguous. if one person answers that question, then undoubtedly another person will come and disagree and then you will have a flame war.

Ill try to help you as best as i can, but dont expect an engineer's approach.

if your asking about maximum horsepower numbers N/A then your basically just asking about who has the motor with the biggest cam, biggest heads, and biggest intake. One of the most basic basic things I always hear is Torque X RPM / 5252 = HP

Its so simple its almost stupid. To get torque we need cylinder pressure and volumetric efficiency. this always peaks somwhere right? and to get RPM all we gota do is spin the heck outa the motor.

SO basically all you gota do is put the biggest cam/head/intake you can fit on the motor and spin it as high as you can and bingo you have a peak torque way up there and so are your HP Numbers. thats probably not the best idea for the street, however, so i assume your just curious about the max HP of a N/A 350 block being spun as high as the limitations imposed by its rotating assembly. peak HP doesnt always win races however, its whats in between that counts the most, unless you can keep the rpms right there at your peak the whole way down the track.

so that is where your peak hp numbers will come into play VS different motor, such as L98 VS L03 VS LS1.

you simply cannot spin a stock L98 rotating assy to 8000 rpms. but you can spin a small journal 327 forged rotating assy to 8000 or even higher. that motor, even though smaller, can technically make more horsepower simply because of its stronger rotating assy thus you can use even bigger heads and cam and so forth. now take the L98 and fill it full of forged stuff and then you can spin THAT to 8000 or better. it will then make more power.

I better stop before i ramble myself to death. point it, peak HP in a N/A motor is goina be better when your peak torque moves to the right. the further over you go, however, the more stress imposed on everything. it becomes a gamble once you go past 6,000 RPMS on most factory cast parts. so if we are talking about a factory L98 rotating assy in N/A format then i would say spinning it to about 6000 with a good head / cam combo could make between 400-450 horsepower, but peak torque(VE%) will still be around 4800 rpms. until you upgrade the rotating assy or throw a power adder on the thing you will usually never see over 450 FWHP out of a factory L98 rotating assy, or any other N/A factory 350 with cast parts, simply because of the RPM restraint.

ok im done.

Ian_F

Wow. I completely agree with everything that kingtal0n said. It really is impossible to know what the max. HP of any engine is. Too many variables and not enough constants. A better question might have been "what is the most horsepower you can get out of a naturally aspirated, stock intake L98." But of course intake porting and runner siamesing would be allowed. Even then, it would be an extremely difficult question to answer.

25THRSS

Please don't say FWHP anymore. It really bugs me for some reason, lol. No f body ever made was fwd, they were all rwd. When referring to a rwd car in hp terms, the correct way to say it would be RWHP! Sorry, that just bugs me for some reason. Also 422 ci isnt the max cubes for an LS1 and either is 500 hp for a stroker motor. There are plenty of guys making insane power with LS1's. It really all depends on the setup, like any other motor.

Martin Steel

Kingtal0n: Thank you for your contribution, but I am already aware of the principals you described. That type of information is available in many textbooks on the subject.

If I could refer everyone to my first posts where I am asking for descriptions of motors in vehicles driven my members of this board.

- “Who owns the most powerful normally aspirated L98 on Thirdgen.org?”
- “There has to be a lot of you that can help. Please describe your combination and include HP (preferably rear wheel) and a cost breakdown.”

I will again apologize for any ambiguity in my posts.
I am looking for responses like the following hypothetical example:

L98 out of my ’89 GTA, now a splayed 4 bolt 406CI, forged Cola crank w/ polished journals $1000, eagle I beam rods $500, forged 10:1 pistons $1500, ported 190 Air Flow heads (2.02/1.60) $1500, Crane cam 214/224 $300, Hooker ceramic coated headers $600, ported Lingenfelter Super Ram $1200, 1000 CFM throttle body $600, 55# injectors, factory ECU, etc., etc.
Machine work and rebuild labor $1200
Produced 400 RWHP on a Dynojet through a 3000 stall converter, GER 700R4, and a
12 bolt rear. Also ran 11.80 at sea level on drag radials

Greasemonkey

FLYWHEEL Horsepower = FWHP.

25THRSS

I know now that he meant fly wheel hp, but front wheel hp is abreviated that way as well. I misunderstood him. My fault. It just really bugs me when people say front wheel hp for some reason, lol.