1980 Engine Rebuild
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Joined: Dec 2010
Posts: 50
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From: Statesville NC
1980 Engine Rebuild
I'm rebuilding my L-48 engine.
I tore the engine down this weekend and I was amazed how little wear has taken place with 91,000 miles. The rod bearings showed the most wear and no sludge. This car must of really been taken care of before I purchased it.
I'm going to keep the engine bay completely stock looking using the stock carb, intake, and exhaust. 4spd, PS, PB, and AC. Car is only going to be used for cruisins. I do have a set of 186 heads with .194/.150 valves that will be used for the rebuild.
My plan is to use the 186 heads and purchase flat top pistons. My CR should be close to 10:1 and I already use 93 octane ethanol free gas.
What hydraulic flat tappet camshaft would be a good choice?
A friend recommended a howards camshaft with 450/450 lift 213/213 duration @ .050. I was thinking something like a L79 or L82 cam but in a modern grind.
Any recommendations?
I tore the engine down this weekend and I was amazed how little wear has taken place with 91,000 miles. The rod bearings showed the most wear and no sludge. This car must of really been taken care of before I purchased it.
I'm going to keep the engine bay completely stock looking using the stock carb, intake, and exhaust. 4spd, PS, PB, and AC. Car is only going to be used for cruisins. I do have a set of 186 heads with .194/.150 valves that will be used for the rebuild.
My plan is to use the 186 heads and purchase flat top pistons. My CR should be close to 10:1 and I already use 93 octane ethanol free gas.
What hydraulic flat tappet camshaft would be a good choice?
A friend recommended a howards camshaft with 450/450 lift 213/213 duration @ .050. I was thinking something like a L79 or L82 cam but in a modern grind.
Any recommendations?
Le Mans Master
Joined: Mar 2008
Posts: 5,948
Likes: 72
From: Oxford MA-----You just lost the game!!!!
I think you should consider upgrading the stock exhaust, it's pretty restrictive. Also, plan on recurving the distributor. Here's a good cam for your consideration, it should have enough duration to allow a reasonable DCR.
http://www.summitracing.com/parts/su...make/chevrolet
Scott
http://www.summitracing.com/parts/su...make/chevrolet
Scott
Last edited by scottyp99; May 12, 2014 at 01:14 PM.
Burning Brakes
Joined: Mar 2010
Posts: 987
Likes: 7
From: Surrey British Columbia
I agree with Scott about the exhaust. If you're going to give the engine a bit of a boost, there's really no sense in restricting it with that stock exhaust. Shorty headers into a high flow cat is the least you can do and it will make a difference. By the way, the stock intake with the dual snorkel set-up is the best cold air intake for the '80. Good choice.
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Joined: Dec 2010
Posts: 50
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From: Statesville NC
well it does have a high flow cat, and mufflers. With the stock engine I didn't feel any exhaust back pressure like I have in other stock 350's I've owned.
Once the car is 35 years old I will remove the cat and run true duals. I'll still use the stock exhaust manifold. So that will be the end result. I just have to go through one more state inspection before that fun can begin.
Once the car is 35 years old I will remove the cat and run true duals. I'll still use the stock exhaust manifold. So that will be the end result. I just have to go through one more state inspection before that fun can begin.
Le Mans Master
Joined: Mar 2008
Posts: 5,948
Likes: 72
From: Oxford MA-----You just lost the game!!!!
well it does have a high flow cat, and mufflers. With the stock engine I didn't feel any exhaust back pressure like I have in other stock 350's I've owned.
Once the car is 35 years old I will remove the cat and run true duals. I'll still use the stock exhaust manifold. So that will be the end result. I just have to go through one more state inspection before that fun can begin.
Once the car is 35 years old I will remove the cat and run true duals. I'll still use the stock exhaust manifold. So that will be the end result. I just have to go through one more state inspection before that fun can begin.
Scott
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Advanced
Joined: Dec 2010
Posts: 50
Likes: 0
From: Statesville NC
My first car was a 72 Monte Carlo. Single exhaust and the first bright idea I had was to put a 4 barrel carb on it. When the second butterfly opened up you felt no boost. It sounds like a cow screaming and would sometimes cause the exhaust pipe to separate from the muffler. That's feeling exhaust pressure.
After headers and dual exhaust it would tip a cow over in comparison.
I experienced something similar with a 99 truck after putting dual exhaust on.
I will probably have a similar feeling when I put duals on this vette. But based on experience I am not expecting that much of a dramatic effect. I also have a 190hp L-48 in the vette right now. With the piston, heads, and cam upgrade this car will feel different and the pressure may be different. Just seems to breathe good right now.
Back in the day with limited resources you tuned by feel. You were not always right, its just how things were done.
After headers and dual exhaust it would tip a cow over in comparison.
I experienced something similar with a 99 truck after putting dual exhaust on.
I will probably have a similar feeling when I put duals on this vette. But based on experience I am not expecting that much of a dramatic effect. I also have a 190hp L-48 in the vette right now. With the piston, heads, and cam upgrade this car will feel different and the pressure may be different. Just seems to breathe good right now.
Back in the day with limited resources you tuned by feel. You were not always right, its just how things were done.
Le Mans Master
Joined: Mar 2008
Posts: 5,948
Likes: 72
From: Oxford MA-----You just lost the game!!!!
Ah, so, basically, it's just something you develop a "feel" for, after experiencing non-performance and performance exhaust systems, before and after. That's pretty cool.
Scott
Scott
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Le Mans Master
Joined: Oct 2010
Posts: 6,937
Likes: 848
From: melbourne florida
2023 C3 of the Year Finalist - Modified
the L-82 cam is very good, excellent with 10-1 compression.i agree on aluminum heads lots of good aftermarket heads. im not impressed with the l-98 heads .and i know people like the vortec heads but they are overrated.