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10/29/11 1:58am - Original Message: 'How do I get more performance from a stock 1974 L82?'
Former Member
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, - Australia

1974 L82 Silver with black interior. Factory M21, Power windows & steering. Side pipes just because I can.

Joined: 7/11/2011
Posts: 18
Hi all 

Just got the new toy and while my car is totally stock in under the hood, I would like to try to get as much performance from the stock motor as possible.

I don't want to open the motor or do any head work etc - too costly and Im not that desperate of extra horses - just want to utilise what I have!

Im thinking the best way is to change the air cleaner and unit and also a new carbi..

If anyone knows what modern carbi would suit my motor the best (I want a brand new carbi) I would love to hear suggestions. As well as air cleaners...


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10/29/11 10:32am - Reply: 'Re: How do I get more performance from a stock 1974 L82?'
Former Member
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Dutchess County, NY - USA

White '79 Corvette. It's a driver.

Joined: 8/27/2007
Posts: 2484


I think the only way you're going to get real noticeable gains in your L-82 is by doing  a cam and heads. Other than that you won't really feel any "seat of the pants" impropvements.
I speak from experience. My '79 has an L-48. I have done everything except a cam and heads. It runs great but it's not a monster by any means.
The best, most noticeable gain in performance I have done is getting the original Q-Jet carb. rebuilt. It is my opinion that the Q-Jet is the best carb. for our 350's when the rebuilder does the job well.
Don't make your '74 a money pit. Enjoy it!

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10/29/11 11:31am - Reply: 'Re: How do I get more performance from a stock 1974 L82?'
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Frederick, MD - USA

1969 convertible L71 427/435 4-speed black interior

Joined: 9/8/2003
Posts: 3398
I agree.  Without a cam change and cylinder head work about all you can do is some improvements around the edges, so to speak.  You can add a different intake manifold which is some help, but the selection of intakes that will fit under a stock C3 hood are limited.  An Edelbrock Performer is one of the few that fits and will help, but you won't see a huge improvement.

Having your Q-jet rebuilt by someone who knows them will be a help.  Adding electronic ignition will help starting but won't be a huge improvement either...it mostly reduces maintenance but doesn't help much in and of itself.   

Adding exhaust headers can make a noticeable difference, but selection is important to get the right set that does what you want.

Do all of those and you can notice a distinct difference, but still...it will require more serious work to see a substantial increase in performance.

I had a '78 L82...I added the Edelbrock Performer intake, had the Q-jet rebuilt, and kept the stock exhaust manifolds, eliminated the catalytic converter and installed a true dual exhaust (which a '74 should still have)...it made a nice difference.  Not so much stump pulling torque but a it was really a nice, reasonably power engine that did everything I wanted.

Poet...Mystic...Soldier of Fortune. As always...self-absorbed, adversarial, c o c k y and in general a malcontent.

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