I am the new owner of a 1978 Corvette with the L82. I was disappointed with the performance so I came here and did some research. Here is what i plan to do in order. I would appreciate any and all advice.

1. Exhaust - I plan on replacing the exhaust on my vette first. I am going to remove the cats and go with different mufflers. Do I go ahead and put on headers? If so will it hurt anything to have headers without other mods? I think I will go with flow masters but want something mild. Suggestions on mufflers?

2. Intake - after exhaust I will put on Edelbrock Performer and Holley carb. I read the Holley 600 should work well

This will be it for awhile. I plan on cam and heads after these 2.

Thanks in advance for advice

 

I'd go performer R.P.M. and 3310 Holley 750 if your doing more later the others would work against your future mods. a quadrajet is 750cfm.

 

Your Q-jet is a good carb and I wouldn't waste my money on a Performer, similar to your stock intake. Get a decent exhaust on it to start and depending on mileage (condition of the short block) maybe some good flowing heads, advance the cam 4 degrees or replace with more aggressive cam. If you want a better intake consider Weiand Stealth, Holley Street Dominator or RPM performer and a Holley 750. If you want a nice mellow sound look at Dynomax Turbo mufflers, flow masters are not mild. You can install headers anytime with your new exhaust, it wont hurt anything.

 

How many miles on the motor? And, is it the original exhaust system? I'm interested depending on condition.

 

The motor has 65000 original miles. Exhaust is stock

 

Another avenue for an improvement is change the 3 speed auto (if it is an auto) to a 4 speed overdrive. Doesn't necessarely improve HP but does lower the revs at speed and makes the car more drivable. I put in a 700R and it was the best upgade IMO.

Regard
Robert

 

When you get to the intake replacement.........buy a new HEI distributor. Buy the advance spring kit ($5) and place the weakest springs on the advance posts. I use an Accel Super Coil but you can buy which ever aftermarket coil you like. After the distributor upgrades, get good wires and enlarge your plug gaps to .060

 

My stock '79 L82 4 speed just needed a good tune to begin to wake it up. A fellow forum member helped me to do this. We ended up with 1 stock distributor spring, and one gold spring (Mr. Gasket from Jegs). Idle was set at 19 degrees btc @750 rpm, and advance all in at 36 degrees at 2500-2600 rpm. Now running premium gas. But it is much more alive than the stock tune.

 

G-Stig and snoopykissedlucy are right, look at the ignition and this post....



http://forums.corvetteforum.com/c3-t...long-post.html

 

Hey. I know that I'm probably opening a can of worms here since carbs seem to be like religion to a lot of people, but I really like the quadrajet on mine. I have just over 100k on my '80 and the q-jet works great. Very street-friendly but still performs decent when you get your foot in it. I've driven one of my friends' trucks with an Edelbrock performer carb in it and I was amazed by how poor the part throttle response was. That may have just been tuning, but his truck essentially had two speeds: idle and WOT. Just my thoughts.

 

The truth is getting an aftermarket carb to work correctly is much more difficult than people realise. It's not a simple plug-and-play swap if you want your car to work correctly.

Quadrajets will pass emissions, only the smog legal Edelbrock and Holley Models have a chance (not all of them have fuel bowl vents which is key).
Quadrajets have an idle solenoid so your car won't stall when you turn the AC on, others either do not have them or require an additional kit.
Quadrajets are spread bore with smaller primaries, resulting in better fuel economy.
Quadrajet choke mechanism works. Using the choke on aftermarket carbs usually requires some modifications (requires an adapter for hot choke conversion, more money, or wiring for an electric).
Quadrajets fit under your hood. Aftermarket carbs set at different heights which may result in you needed to purchase a new air cleaner to make it fit.

My car came equipped with an Edelbrock when I purchased it. I spent hours upon hours researching the different aftermarket carbs . I finally came to the conclusion that Quadrajets truly are the best carburetor for my car. After my experience with the Edelbrock and trying to make things work properly I made the wise decision to chuck it and switch back to a numbers matching Quadrajet that I found on ebay.

Quadrajets will function well and deliver the performance you will need. Take the time to rebuild it properly, get the throttle shafts rebushed, and have it well cleaned. You will be much happier with a Quadrajet in the end.

I agree with others on the intake as well. The Edelbrock Performer is a complete dud and is really no different than your L82's stock intake. The performance gains are pretty negligible.

You'll have to end up going to a much more agressive intake, I won't go into which one here but there is always a catch. Very few aftermarket intakes will offer provisions for your hot air choke and/or EGR. If you feel you don't need EGR and you don't mind a car that's a little harder to start on a cold day then no big deal.

Consider using a stock intake and having it ported. There are plenty of posts lurking about people running 11's on stock intakes with Quadrajets.

The cold hard fact is the heads and to a lesser extent, your camshaft, is where the power will be unlocked.