1981 Engine upgrade question
Thread Starter
Heel & Toe
Joined: Feb 2024
Posts: 18
Likes: 3
From: Southern California
1981 Engine upgrade question
I recently had the engine in my 81 rebuilt from the bottom end up. New pistons, full roller rocker setup, bigger cam, new AFR heads.
I kept the stock carb and computer setup for smog purposes here in California. Mechanic called me today saying that he thinks I
need a new computer chip. He drove it today for the first time and said power wise, it doesn't seem any different to him. I haven't
driven yet. Has anybody else done a similar rebuild and had to upgrade the ecm to notice changes or any ideas onhank why it wouldn't
seem any different? I expected a significant power increase.
Thanks
Ken
I kept the stock carb and computer setup for smog purposes here in California. Mechanic called me today saying that he thinks I
need a new computer chip. He drove it today for the first time and said power wise, it doesn't seem any different to him. I haven't
driven yet. Has anybody else done a similar rebuild and had to upgrade the ecm to notice changes or any ideas onhank why it wouldn't
seem any different? I expected a significant power increase.
Thanks
Ken
Melting Slicks
Joined: May 2021
Posts: 2,274
Likes: 1,318
From: Fleming Island, FL
Two things here. 81 Corvette came with a 2.87 rear. 3.55's would have gone a long way in terms of performance and no one would have been the wiser. I would still do a gear change. Forgot about off the shelf chips. Do you know the air/fuel ratio at WOT? You probably need different secondary metering rods and a bump ignition timing. Is a CARB approved high-flow/honeycomb style catalytic converter available for your car? Also I heard that there's a bill pending in California that's going to exempt 77 to 84 cars starting in 2 years from emissions testing. Also third generation Camaro forum maybe a better place to ask. They seem to have a lot of guys in California with fast cars that pass their emissions testing.
Last edited by Fly skids up!; Apr 21, 2026 at 07:36 AM.
Thread Starter
Heel & Toe
Joined: Feb 2024
Posts: 18
Likes: 3
From: Southern California
I had the rear gears changed out to 3.55 about 6 months ago and had CARB high flow cats installed when I switched the exhaust over to true dual about a year ago.
Not sure what the air/fuel ratio is. I've heard about the proposed emissions changes but I've been hearing that for at least a year in one form or another. I hope it happens.
Not sure I'll even be in California anymore before that ever happens.
Not sure what the air/fuel ratio is. I've heard about the proposed emissions changes but I've been hearing that for at least a year in one form or another. I hope it happens.
Not sure I'll even be in California anymore before that ever happens.
