1977- engine issue. What to do?
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Joined: Jul 2012
Posts: 91
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1977- engine issue. What to do?
Hi all- I have a 1977 Corvette that’s all original and stock. After 50 years I think the engine is beginning to drop a valve or something. Idle and accelerator are fine, but when you decelerate there’s a ticking sound coming from the engine.
Three questions:
1) anyone had this happen and it not be an internal engine issue?
2) is it worth trying to rebuild the engine if that’s what it is?
3) if the engine is bad, I’m considering a new engine with a little more aggressive sound and more horsepower. I’d prefer something that drops in and bolts up without significant drive train modifications. I’m not wanting a drag car type of sound, but something that sounds more like a muscle car that isn’t insanely loud for my kids that ride in the car. Any suggestions? Anyone done this with videos and specs?
Three questions:
1) anyone had this happen and it not be an internal engine issue?
2) is it worth trying to rebuild the engine if that’s what it is?
3) if the engine is bad, I’m considering a new engine with a little more aggressive sound and more horsepower. I’d prefer something that drops in and bolts up without significant drive train modifications. I’m not wanting a drag car type of sound, but something that sounds more like a muscle car that isn’t insanely loud for my kids that ride in the car. Any suggestions? Anyone done this with videos and specs?
Melting Slicks
Joined: Apr 2021
Posts: 2,676
Likes: 2,126
From: Minnesota
If you upload a video to YouTube you can then post it on here. There’s a lot of things it could be. Are you positive it’s from the engine and not the transmission, rear end, U-joints, or wheels?
If you go down the rebuild route I would go with the recommendations given in this thread.
As for a new engine there’s many different places that sell complete or nearly complete small blocks that bolt in and use the same accessories as what came with the car. Blueprint Engines seems to be a popular choice on here. Here’s their website.
If you go down the rebuild route I would go with the recommendations given in this thread.
As for a new engine there’s many different places that sell complete or nearly complete small blocks that bolt in and use the same accessories as what came with the car. Blueprint Engines seems to be a popular choice on here. Here’s their website.
Last edited by Piersonpie; Feb 22, 2026 at 12:06 PM.
Race Director
Joined: May 2006
Posts: 18,706
Likes: 2,573
Hi all- I have a 1977 Corvette that’s all original and stock. After 50 years I think the engine is beginning to drop a valve or something. Idle and accelerator are fine, but when you decelerate there’s a ticking sound coming from the engine.
Three questions:
1) anyone had this happen and it not be an internal engine issue?
2) is it worth trying to rebuild the engine if that’s what it is?
3) if the engine is bad, I’m considering a new engine with a little more aggressive sound and more horsepower. I’d prefer something that drops in and bolts up without significant drive train modifications. I’m not wanting a drag car type of sound, but something that sounds more like a muscle car that isn’t insanely loud for my kids that ride in the car. Any suggestions? Anyone done this with videos and specs?
Three questions:
1) anyone had this happen and it not be an internal engine issue?
2) is it worth trying to rebuild the engine if that’s what it is?
3) if the engine is bad, I’m considering a new engine with a little more aggressive sound and more horsepower. I’d prefer something that drops in and bolts up without significant drive train modifications. I’m not wanting a drag car type of sound, but something that sounds more like a muscle car that isn’t insanely loud for my kids that ride in the car. Any suggestions? Anyone done this with videos and specs?
Race Director
Joined: Mar 2016
Posts: 14,340
Likes: 8,144
From: Napa Valley California
Another cause besides those mentioned above could be a loose worn out timing chain that’s slapping around in the timing cover.
They will tighten when the torque in the engine is applied but will slap around during deceleration.
If you find it’s time to rebuild the engine, find a good well recommended machine shop in your area and have your original engine rebuilt.
There’s several things you can do to wake up that 77 engine.
Depending on where you live and the emission laws you could deck the block and heads for a slight increase in compression ratio, swap the intake manifold, install a mild camshaft, have Lars rebuild the original carb and have a nice exhaust system put on without a lot of expense.
If the engine isn’t broken then a good rebuild with new pistons, rings, bearings, hone or bore and a valve job can be done for a reasonable cost.
They will tighten when the torque in the engine is applied but will slap around during deceleration.
If you find it’s time to rebuild the engine, find a good well recommended machine shop in your area and have your original engine rebuilt.
There’s several things you can do to wake up that 77 engine.
Depending on where you live and the emission laws you could deck the block and heads for a slight increase in compression ratio, swap the intake manifold, install a mild camshaft, have Lars rebuild the original carb and have a nice exhaust system put on without a lot of expense.
If the engine isn’t broken then a good rebuild with new pistons, rings, bearings, hone or bore and a valve job can be done for a reasonable cost.
Last edited by OldCarBum; Feb 23, 2026 at 01:27 PM.
Race Director
Joined: Mar 2017
Posts: 11,931
Likes: 4,497
From: Virginia
Photos, and especially a video, can really help with diagnosing over the internet.
With the help of the Forum, I found the source of the clunking in my 80 in this way.
https://www.corvetteforum.com/forums...nd-videos.html
With the help of the Forum, I found the source of the clunking in my 80 in this way.
https://www.corvetteforum.com/forums...nd-videos.html
Instructor
Joined: Apr 2018
Posts: 165
Likes: 92
From: Buxton ME
When checking for an exhaust leak, don't forget to check the choke tube plate on the exhaust crossover on the intake manifold. I chased that one for a couple weeks. Use a length of plastic hose with one end stuck in your ear, you'll be surprised how loud it can be when you find it.
Good advice to read Leigh1322's post. Long but thorough.
Good advice to read Leigh1322's post. Long but thorough.
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