Question: 1980 L82 Headers
- Thread starter fitter81
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- Ottawa, Canuckistan
- Corvette
- 1973 coupe L82 (gone as casualty of divorce)
As odd as this might sound, I did the opposite... When I found a good set of ram horn exhausts, I removed/replaced the rusty headers that some previous owner installed. The factory exhaust manifolds flow well enough to handle the average L82... even with the smog pump removed. Mind you, I was trying to bring the 73 back to looking factory despite non-original block...
Mac
Mac
fiberglass
Member
it depends
Depends on how deep you want to go into it how much you want to spend etc.I would put a 400 crank a nnice can and a set of trick flow heads to start with. But that's what I always do. Like I said it depends.
Depends on how deep you want to go into it how much you want to spend etc.I would put a 400 crank a nnice can and a set of trick flow heads to start with. But that's what I always do. Like I said it depends.
Wayback
Well-known member
I installed Hooker Headers on the old 78 L82,all smog removed. Used a dual exhaust Hooker Kit,no mufflers,used twin tip resonators. While I was at it did a Hurst shifter, R&R'd the Qjet with a Holly Qjet replacement carb,Acell HEI dizzy,manual shut of valves to the heater core, ETC.I like loud,1st thing I did was install Hooker side pipes on the old 68 L71/with a Hurst shifter also.I do all my own work, Ill proably do a dual chambered exhaust on the 93 eventually.I eliminated the mufflers on the old 85 also along with some mods.
N o
C orvette
R emains
S tock
in my book,had pics on Web Shots,Photo Bucket,all gone now.
Side shot of the muffler elimation,had this pic on my desk top.
N o
C orvette
R emains
S tock
in my book,had pics on Web Shots,Photo Bucket,all gone now.
Side shot of the muffler elimation,had this pic on my desk top.
Last edited:
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- Edgerton, Ohio, United States
- Corvette
- 1959 black 270hp (9/2/69) 1981 Beige L81(10/20/80)
The L82 is a pretty good engine to start with if it's in good condition. You are on the right track starting with the exhaust system since you won't realize the full benefits of engine mods if the exhaust can't flow efficiently out the back. Some of the Corvette parts houses offer real dual exhaust kits with low restriction mufflers for your car that will get you away from that single pipe running to the back. I'm not sure if you have emmissions inspection where you live but getting that old pellet cat off of there will be a big help.
Next I'd tackle the distributor. These smog era distributors had a very lazy advance curve. Recurving it to around 34 degrees total advance all in by 3000 rpm with initial timing set to 12-14 degrees will really wake it up. If you have a dial back timing light this is easy to do yourself with one of the spring and weight kits from Summit, Jegs and others. The springs determine how fast the advance comes in and the weights determine the rate this happens. You may end up with 2 alike springs or 2 different springs and in some cases the stock weights work out best. it's a trial and error thing. It's also necessary to determine that your timing mark on the balancer is on the money. Sometimes the ring slips and the mark can be several degrees off screwing up everything you do to the distributor. Finding top dead dead center and determining if your timing mark is dead on is covered in many YouTube videos. It's pretty easy to do. If your mark is way off your ring has slipped on the balancer and you need to replace the balancer to avoid it coming off and tearing up the radiator and everything else on the front of the engine. If it's only off by a couple of degrees that's within production tolerances and ok to run. In this case you can install a degreed harmanic balancer cover available from Summit, Speedway Motors and others for a fairly cheap price. You just remove the crank pulley, slide the cover over the balancer and reinstall the pulley. You now have a fully degreed balancer with all the marks in the correct place and you can tune your distributor with a standard timing light.
If you are not comfortable doing the distributor calibrations yourself there should be a shop close to you that can do it for you. Ask around or check online. You will still want to verify that your timing mark is on the money though.
Keep in mind that a Q-Jet will flow all of the CFM that your L82 will ever need but these smog era Q-Jets are calibrated way lean and with the headers it will lean out even more. Back when Rochester Q-Jet parts were pleniful at the Chevrolet dealer parts counter I'd just select metering rods, metering rod hangers and jets from an application back in the '60s up to about 1970 before emmissions concerns ruined performance calibrations and install them into the smog era Q-Jet I was tuning. This might not have been the most perfectly accurate way of doing it but even then metering rods were expensive and buying a selection of different sizes to dial in a carb was expensive. Here's an example: If I was tuning a mid '70s 350 4bbl I'd select parts for a late '60s 350/300 horse or if it was cammed I'd use '69 Corvette 350/350 horsepower rods and hangers. Even though the factory parts were still a compromise they were far better for performance and mileage than the fat, lean, smogger ones that were in the '70s carb. You could definately feel the difference on the street. I haven't done one in a while so I'm not sure what is available these days. I see that Edelbrock has a good selection of Q-Jet rods and jets and also there is stuff on Ebay. I'd also buy the Rochester performance carb manual available from Summit ect. to help me pick out what rods and parts I want to start with.
So with your exhaust, ignition and carb optimized you will be able to tell if you are happy with the L-82 or if you want to go to the more expensive mods like a 383 stroker crank kit and aluminum heads.
Tom
Next I'd tackle the distributor. These smog era distributors had a very lazy advance curve. Recurving it to around 34 degrees total advance all in by 3000 rpm with initial timing set to 12-14 degrees will really wake it up. If you have a dial back timing light this is easy to do yourself with one of the spring and weight kits from Summit, Jegs and others. The springs determine how fast the advance comes in and the weights determine the rate this happens. You may end up with 2 alike springs or 2 different springs and in some cases the stock weights work out best. it's a trial and error thing. It's also necessary to determine that your timing mark on the balancer is on the money. Sometimes the ring slips and the mark can be several degrees off screwing up everything you do to the distributor. Finding top dead dead center and determining if your timing mark is dead on is covered in many YouTube videos. It's pretty easy to do. If your mark is way off your ring has slipped on the balancer and you need to replace the balancer to avoid it coming off and tearing up the radiator and everything else on the front of the engine. If it's only off by a couple of degrees that's within production tolerances and ok to run. In this case you can install a degreed harmanic balancer cover available from Summit, Speedway Motors and others for a fairly cheap price. You just remove the crank pulley, slide the cover over the balancer and reinstall the pulley. You now have a fully degreed balancer with all the marks in the correct place and you can tune your distributor with a standard timing light.
If you are not comfortable doing the distributor calibrations yourself there should be a shop close to you that can do it for you. Ask around or check online. You will still want to verify that your timing mark is on the money though.
Keep in mind that a Q-Jet will flow all of the CFM that your L82 will ever need but these smog era Q-Jets are calibrated way lean and with the headers it will lean out even more. Back when Rochester Q-Jet parts were pleniful at the Chevrolet dealer parts counter I'd just select metering rods, metering rod hangers and jets from an application back in the '60s up to about 1970 before emmissions concerns ruined performance calibrations and install them into the smog era Q-Jet I was tuning. This might not have been the most perfectly accurate way of doing it but even then metering rods were expensive and buying a selection of different sizes to dial in a carb was expensive. Here's an example: If I was tuning a mid '70s 350 4bbl I'd select parts for a late '60s 350/300 horse or if it was cammed I'd use '69 Corvette 350/350 horsepower rods and hangers. Even though the factory parts were still a compromise they were far better for performance and mileage than the fat, lean, smogger ones that were in the '70s carb. You could definately feel the difference on the street. I haven't done one in a while so I'm not sure what is available these days. I see that Edelbrock has a good selection of Q-Jet rods and jets and also there is stuff on Ebay. I'd also buy the Rochester performance carb manual available from Summit ect. to help me pick out what rods and parts I want to start with.
So with your exhaust, ignition and carb optimized you will be able to tell if you are happy with the L-82 or if you want to go to the more expensive mods like a 383 stroker crank kit and aluminum heads.
Tom
Wayback
Well-known member
Some pics after I sold it to Steve,he bought my old 85 also. I work with his brother.
Russ Corvette Restoration, LLC. added 11... - Russ Corvette Restoration, LLC. | Facebook
org factory color was light beige,was repainted silver when I bought it,redone in red.
Resold at the Atlantic City show,I wonder who bought it ?
Russ Corvette Restoration, LLC. added 11... - Russ Corvette Restoration, LLC. | Facebook
org factory color was light beige,was repainted silver when I bought it,redone in red.
Resold at the Atlantic City show,I wonder who bought it ?
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