81 carb replacement
Thread Starter
6th Gear
Joined: Apr 2009
Posts: 6
Likes: 0
From: Dallas TX
81 carb replacement
anyone got any thoughts on a replacement carb for my 81..i was thinking of a edelbrock thunder series.. with electric choke.. not sure if i need egr.. or non egr... and is a 650 cfm enough.... any opionios would be helpful..
Le Mans Master
Joined: Jan 2006
Posts: 9,192
Likes: 27
From: Boca Raton Florida
That wopuld be a step down. The carb you have is a 750 and is quite capable of running your engine at 300 or more HP. If it has a problem, get that fixed and spend your $$ on other items like a bigger cam, headers etc. The 81 also came with an Edlebrock 2101 intake which is also a good one, but there are better. Do you have any other mods yet?
Instructor
Joined: May 2006
Posts: 223
Likes: 1
From: Kennesaw GA
The '81 has a computer controlled quadrajet. if you change it out with an aftermarket one, you may have issues with the 'check engine' light as well as the computer controlled HEI. I would suggest having a competent rebuilder look at your original carb, or removing all the computer equipment and going with a new carb and HEI.
Le Mans Master
Joined: Jan 2006
Posts: 9,192
Likes: 27
From: Boca Raton Florida
If your thinking mods, you will need a better exhaust no matter what you do. Fix the issues you have and you will be surprised what that thing will do. A rebuild on that carb will be a lot less than a new carb and all the attendant mods and issues you will have by going to some other carb setup
Le Mans Master
Joined: Jan 2006
Posts: 9,192
Likes: 27
From: Boca Raton Florida
The 81 came with SS Headers instead of a cast manufold, it has AIR tubes welded into the top of each pipe that are in turn welded to annother pipe that the AIR pump hose connects to. They are headers, albeit somewhat restrictive, but better than exhaust manifolds.
Thread Starter
6th Gear
Joined: Apr 2009
Posts: 6
Likes: 0
From: Dallas TX
yea.. they are somewhat headers.. not nice ones by any means.. i have removed the a i r system.. so you would change the carb and distrubutor both together... ... the motor only has 48k on it originally.. of course it leaks oil like a seive... does the electric choke cause anyone else problems... if the engine is warm and you touch the gas pedel it is flooded...
lance
lance
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Race Director
Joined: Apr 1999
Posts: 11,520
Likes: 13
From: CORVETTE 77 385 C.I. TEXAS
Q-J has plugs in the carb body that can leak & can be fixed.
If you need to pass emissions test, egr needed.
Holley has a spread bore carb that bolts on in place of the Q-J.
Last edited by Ganey; Apr 13, 2009 at 01:43 PM.
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,118
From: Crossville TN
A 'flooding' carb usually means that the needle valve/seat and/or the float are bad. Those are easy to fix with a simple rebuild kit. You can check out the function of the electronic portion of that carb using the procedure called out in the Chevrolet Chassis Service Manual for 1981. You just need a volt-ohmmeter to check it. I would suggest that you check out the function of your carb first. If the electronic part is fine, just buy a rebuild kit for your carb (NAPA or other quality parts store) along with a new [foam-core] float as a separate item. Clean the outside of the carb with carb cleaner, then tear it down. Be certain to blow out all passages to get rid of any collected "stuff". For about $50 you should be "good to go".