Early 86 top end build
Thread Starter
Drifting
Joined: Oct 2020
Posts: 1,398
Likes: 438
From: Marlton NJ
Early 86 top end build
Hi all,
I am looking for some advice. I plan on rebuilding the top end of early 86 Corvette cast iron head L98. I am looking to be something in 400hp 400+ torque.
My first question is can I get to those numbers with cam, heads and TPIS intake ? I am looking at AFR 195 heads, but which camshaft will work well for what I am trying to do ?
The car already has air pump delete and headers with Catalytic converters deleted up front. Still has the main cat under the car and a Corsa cat back exhaust.
Thanks for your input.
I am looking for some advice. I plan on rebuilding the top end of early 86 Corvette cast iron head L98. I am looking to be something in 400hp 400+ torque.
My first question is can I get to those numbers with cam, heads and TPIS intake ? I am looking at AFR 195 heads, but which camshaft will work well for what I am trying to do ?
The car already has air pump delete and headers with Catalytic converters deleted up front. Still has the main cat under the car and a Corsa cat back exhaust.
Thanks for your input.
Le Mans Master
Joined: May 2006
Posts: 7,708
Likes: 266
From: indy indiana
I too have been forced a top end rebuild. Blew a head gasket. LOOKING TO BUY AFR 195 to put back on it. The factory heads just arnt that good. Might as well do a cam swap , headers and a good intake. Dont know if you can change values from your ECM . My Vette is an 86 as well. Ran it a few times here in Indy. Stock it ran a best of 14.03 at close to 100mph. My. and yours, biggest problem is getting power to the ground.Stock, the car spins and fish tails off the starting like. I need better tires., Best of luck and be safe. I am sure some of the guys will give better advice.
Racer
Joined: Aug 2021
Posts: 321
Likes: 44
Stock cat still in the system will need to be changed to a high flow unit to get rid of the restriction in order to get big power numbers. Even the high flow aftermarket TPI is sort of restrictive on the top end. If you really feel 400 horsepower is your target and want to stick with a Tuned Port L98 it will take a big dollar commitment. On the other hand, if you just want a faster car, heads ,cam, intake , and the supporting pieces , will give you a much faster car. L98 is a torque motor that requires a lot of massaging to hit 400 horsepower. Maybe a Supercharger with heads and cam.
Team Owner
Joined: Sep 2001
Posts: 62,160
Likes: 1,733
From: Athens AL
C7 of the Year - Unmodified Finalist 2021
C4 of Year Finalist (performance mods) 2019
The TPiS Miniram intake can get those numbers. If we're talking 400 crank hp, it can be done with the AFR 195s, 1.6RR, MR, Headers. 400 at the wheels is a taller order and I'd be looking for more displacement before I expected that number, and a 383/396 would make it tamer to drive on street.
For cams, I'd look to the LT4 hotcam, or something similar with specs around 220/230 @050", or in the ballpark. You will be forced to have a custom chip burned when this is all installed.
Because you have an 86 with a flat tappet, you can look for something with those specs, or convert to roller cam.
If the OE main cat is whats there, I'd think about replacing that with a modern one.
For cams, I'd look to the LT4 hotcam, or something similar with specs around 220/230 @050", or in the ballpark. You will be forced to have a custom chip burned when this is all installed.
Because you have an 86 with a flat tappet, you can look for something with those specs, or convert to roller cam.
If the OE main cat is whats there, I'd think about replacing that with a modern one.
Le Mans Master
Joined: Sep 2006
Posts: 6,050
Likes: 147
From: Phoenix AZ
2021 C4 of the Year - Modified Finalist
L98
Wondering about your present cam.
have you used synthetic oil or put in anti-wear additives?
could be your cam is going flat, and if so, that fine metal from the cam might be prematurely wearing out your engine.
i would definitely put a dial indicator on the rockers and turn the engine through by hand and take measurements while the cam is supported by the cam bearings.
that will tell you if more work is needed than just a top end. And since you have iron heads, the magnet has lots of places to stick to 😀
have you used synthetic oil or put in anti-wear additives?
could be your cam is going flat, and if so, that fine metal from the cam might be prematurely wearing out your engine.
i would definitely put a dial indicator on the rockers and turn the engine through by hand and take measurements while the cam is supported by the cam bearings.
that will tell you if more work is needed than just a top end. And since you have iron heads, the magnet has lots of places to stick to 😀
Last edited by coupeguy2001; Sep 19, 2021 at 08:02 PM.
