Out-Cast

iTrader: (1)

So I have a chance to get an 1987 Corvette L98 Engine that has work done to the heads and bottom end . What was the HP stock on these engines and with head and bottom end work what kind of HP would it make?
I have the 350 TPI in my car now. And although it's running great I can't pass up this deal On the engine if it's making a lot of HP.
And is my 350 TPI considered an L98 as well?
So I am wondering what is required to make this swap?
ECU Program, exhaust change, fuel pump or any electrical changes??
Any help is appreciated!

bigal55

iTrader: (1)

I think the difference in HP between the Vette L98 and the F-Body L98 was only like 10 HP, not worth the effort of a swap. The bottom end work won't give any HP gain but the head work could, depending on what was done. The only real difference between the Vette L98 and the F-Body L98 is the heads. Beside being aluminum, they had a little better port design. Anything that can be done to the Vette L98 can be done to your L98 so you would be swapping to the same motor. IF the motor is that good of a deal, you may want to pick it up for a later project or insurance incase something should happen to your engine. The swap is a 1 for 1 so there would be zero differences besides the "tune" in the ECM as the aluminum heads allow for more timing. HTH!

Out-Cast

iTrader: (1)

Exactly the answer I was looking for. I just might take it as a spare!
Thanks Bigal55!

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iTrader: (1)

So I am going through 2 people getting info on this motor. The original owner says the motor has an estimated 350-400HP.
A friend said he was in the Corvette and it would Lay rubber for what he said was 400'.
I can get the motor on a Dyno over the Winter and see what it really has I guess!

sofakingdom

iTrader: (1)

The "ratings" of your L98 and the Vette version, were around 10HP different. The Vette version was "rated" around 240 HP in that year. No idea how much of the difference was the motor proper, and how much might be attributed to different exhaust, different negotiation between the liability insurance team and the "luxury tax" team and the CAFE team, etc. Most of those "ratings" aren't very reliable, at best.

Only actual mechanical difference is the details surrounding the heads. Yours have the iron ones, casting 083; the other has aluminum ones, casting 113. Cam is the same. Short block is the same. TPI is the same. (as it would be on a 305 for that matter... either it IS TPI, or it ISN'T, within a given year)

The 113 heads have no EGR provision, so the Vette has the external EGR plumbing (a tube to an exh man instead of a passage over the top to the intake like yours); and the bolt angle of the 2 center bolts in the intake in the aluminum heads is the old-style (all parallel), but your existing iron heads have the 2 center bolts more nearly straight up-down.

Associating the "V" word with ANYTHING automatically boosts the seller's HP quote by at least 100. I thought EVERYBODY knew that. In this case, sounds like more near 150. Pretty much a bunch of diarrhea of the mouth.

But, it'd make a good spare, if nothing else.

Out-Cast

iTrader: (1)

Ya I cant get a straight answer on what is done to it. I don't go for the..."oh it hauls ***" theory.
I want to see it on the Dyno before I spend the time and effort doing a motor swap!
Maybe a 383 Stroker is the way to go??

bigal55

iTrader: (1)

You have to ask yourself, what do you want from an engine and how much money are you willing to spend? If you want big hp numbers, the bigger the motor the easier it is to achieve big hp numbers so a 383 or possibly bigger may be an option. If you are looking at add ons or changing cam and/or heads and/or intakes, either your L98 or the vette L98 will basically cost the same in time and money. This started out as, if this motor has a lot more hp, would a swap be advisable? To, maybe a 383 is the way to go. I don't know what the "cost" of the vette L98 is but for the money, you can probably get 450 hp out of your L98 for the same amount or there about. Do you really know the condition of the vette L98? Why is the seller selling it? Does he want more power? Some things to think about before jumping the gun and "red lighting" so to speak! JMTC

Out-Cast

iTrader: (1)

HThe Engine came out of a wrecked Corvette. And I am only taking 3rd party info that is was reliable and "powerful"
And I only went the 383 question because you guys are telling me the Vette motor is not worth the swap. I don't want a 10 second drag car. I want to keep the car clean as it is now, just maybe a little more power.
Disregard the 383 option because ya that's getting into a lot of work and cash I really don't want to do.

I only thought about an engine swap because 1- the low price of this engine and 2- I will be taking mine out next Spring to clean it up, tune it up and clean up the Engine Bay.
I have to do valve seals and adjust the valves etc.
So do you guys think some cheap reliable mods would be maybe do the heads and say a new header?

Thanks for the input!

RS Chris

If it's only 20-30hp more than what you have, it isn't worth the hassle of swapping. But if you can get if cheap enough it would be a great spare or perhaps a foundation to build another motor. Just depends on if you can get any straight answers about what was done. Buzz words like "bottom end work", "head work", "Vette 350" might fool the average person into thinking it's worth gold, but the rest of us know better. See if you can get any paper work or actual info about the motor before you spend your money. Good luck with whatever you choose.

bigal55

iTrader: (1)

As said before, bottom end work won't produce power but can increase longevity for higher horse power applications. The power gains are going to be made with a cam swap and intake mods (or change to a higher flowing intake) and maybe head work or replacement. These parts must work in conjunction to create more power. Good flowing exhaust is also a necessity to create a complete system. You don't need to do all the mods at once but you must have a clear plan as to the final product and stick to it.

canuckchuck

hey all. I'm doing a swap in my 90 1roc .currently a l98 350 and I have a chance to get a 91vette l98 with low mileage. my understanding is the oil pan ,computer and egr must be changed/modified in order for this swap to work. any info help would be apprecatied!!

rushtk

I know this is an old thread but I hope everyone is still around. I have a 90 c4 vett that needs lots of body tlc. I am about to buy a 92 rs and was saying to myself... self what if we swapped motors and would it be worth it. RS is 305 TBI (which according to this site is a dog and leave it alone), T-Tops and I can get it for 2k. I ask the experts on their thoughts on the subject. Thank you.
P.S. This will eventually be my sons car (he is a sophomore this year) as he gets used to driving. Learning on my 05 magnum rt awd.

Bill91z28

Hi guys I have a l98 out of a 90 corvette with aluminum heads and want to put it in my 91 z28 that currently has a 305 but was concerned about headers all of the headers I see won’t work with the angled spark plugs any tips ?