Camshaft good or bad
Thread Starter
Drifting
Joined: Feb 2013
Posts: 1,464
Likes: 48
Camshaft good or bad
Hello everyone, being I am going to do the timing chain. I decided to replace the camshaft. Being I had popping. Maybe it is a bad lobe. Besides, I'm doing everything but the camshaft. So it just makes sense. I am going to port the lower intake. I have a set of 1.52 roller rockers I plan on installing. It is mostly just enjoying driving my Corvette. Not too much spirited driving and I will not spin it above 4500 maybe 5 grand. I do not want to loose bottom end. With al that in mind. Do any of you have a suggestion for a cam or is there a cam manufacturer I should trust more than the other. Thank you Joe
Ps: does anyone know the specs on the stock cam. I am googling it and get everything but the what I am looking for.
Ps: does anyone know the specs on the stock cam. I am googling it and get everything but the what I am looking for.
Last edited by jseremba; Jan 7, 2023 at 06:58 AM.
Racer
Joined: Mar 2020
Posts: 387
Likes: 148
From: Langton, Ontario, Canada
2025 C4 of the Year Finalist - Unmodified
Hopefully, this chart will help you. I'm assuming that you have no other mods in mind at this time.
Stock cam on an 85 L98 is this:
Intake duration at 050" -202
Exhaust duration at 050" -216
Intake lift with 1.5 rocker: .403
Exhaust lift with 1.5 rocker .415
A slightly better cam that will work with what your intentions are is the Comp Cams 12-402-4
Intake duration at 050" -212
Exhaust duration at 050" -218
Intake lift with 1.5 rocker: .444
Exhaust lift with 1.5 rocker .444
The other one I would look at is the Edelbrock Performer.
Intake duration at 050" -204
Exhaust duration at 050" -214
Intake lift with 1.5 rocker: .420
Exhaust lift with 1.5 rocker .442
These two cams are mild enough that you will still have a dependable bottom end, without much of a lumpy idle, but enough to wake the engine up. Your new rockers alone won't give you much performance improvement, maybe a few more HP, but they're new and you got them, so go with it. For instance, it would change the lift from .420 to .425. Ultimately, you'll have an engine that looks and sounds stock, but only you know it's not.
Back in the day, I used to run a 69 Swinger with a 340 engine, with a Sig Erson cam, that had the same specs as a stock 426 Hemi, that is, 268/268 and .431/.431. This had a moderately lumpy idle, and a low vacuum signal to the carb, and would really be unsuitable for the TPI, without a major retune. It needed the headers and single plane intake to work best, which it did, up to 6500 RPM. Totally not what you are looking for. This is why the milder cams would be better for you in this case.
Have fun!
Stock cam on an 85 L98 is this:
Intake duration at 050" -202
Exhaust duration at 050" -216
Intake lift with 1.5 rocker: .403
Exhaust lift with 1.5 rocker .415
A slightly better cam that will work with what your intentions are is the Comp Cams 12-402-4
Intake duration at 050" -212
Exhaust duration at 050" -218
Intake lift with 1.5 rocker: .444
Exhaust lift with 1.5 rocker .444
The other one I would look at is the Edelbrock Performer.
Intake duration at 050" -204
Exhaust duration at 050" -214
Intake lift with 1.5 rocker: .420
Exhaust lift with 1.5 rocker .442
These two cams are mild enough that you will still have a dependable bottom end, without much of a lumpy idle, but enough to wake the engine up. Your new rockers alone won't give you much performance improvement, maybe a few more HP, but they're new and you got them, so go with it. For instance, it would change the lift from .420 to .425. Ultimately, you'll have an engine that looks and sounds stock, but only you know it's not.
Back in the day, I used to run a 69 Swinger with a 340 engine, with a Sig Erson cam, that had the same specs as a stock 426 Hemi, that is, 268/268 and .431/.431. This had a moderately lumpy idle, and a low vacuum signal to the carb, and would really be unsuitable for the TPI, without a major retune. It needed the headers and single plane intake to work best, which it did, up to 6500 RPM. Totally not what you are looking for. This is why the milder cams would be better for you in this case.
Have fun!
