Challenger RTA
Well-Known Member
I do think the intake is higher for a 4 bbl than a 2 bbl. You could make it work by extending the mounts. Someone might correct me. I'm thinking this one is off a 318 or maybe a 400.
Last edited:
Still need some heavy schooling on carburetors
- Thread starter SRKlegin
- Start date
I'm not here a lot as I don't own an e body 
But felt the need to add a few the comments from an old timer that was around back in the day. The 71 TQ was close to an exact copy of Carters Competition series thermoquad and is highly sought after by restorers and the performance crowd.
The 72 and later were considered "emissions carbs" and not as desirable.
With a spread bore carburetor your choices are few.
I would advise an LD-340 intake or todays equivalent with an AVS of you choice (carter or edelbrock) the big advantage is the easily tunable secondary opening. The Thermoquad also has this feature.
Another option would using your existing intake and a new Demon Spreadbore being sold by Holley who now owns demon.
A concern with all of the choices is parts availability in the future. The Demon could vaporize at any time, the Carter TQ's are questionable parts wise, the Carter/brocks have been around for along time so there is less concern IMO. I would also advise blocking off the heat crossover passages at the cylinder head as todays fuels are not friendly to todays fuels, especially ethanol.
If using the existing intake make sure to block the ports below the primary sided of the carb
But felt the need to add a few the comments from an old timer that was around back in the day. The 71 TQ was close to an exact copy of Carters Competition series thermoquad and is highly sought after by restorers and the performance crowd.The 72 and later were considered "emissions carbs" and not as desirable.
With a spread bore carburetor your choices are few.
I would advise an LD-340 intake or todays equivalent with an AVS of you choice (carter or edelbrock) the big advantage is the easily tunable secondary opening. The Thermoquad also has this feature.
Another option would using your existing intake and a new Demon Spreadbore being sold by Holley who now owns demon.
A concern with all of the choices is parts availability in the future. The Demon could vaporize at any time, the Carter TQ's are questionable parts wise, the Carter/brocks have been around for along time so there is less concern IMO. I would also advise blocking off the heat crossover passages at the cylinder head as todays fuels are not friendly to todays fuels, especially ethanol.
If using the existing intake make sure to block the ports below the primary sided of the carb
Xcudame
Well-Known Member
I have dozens of Thermoquads, so my choice is obvious. I like the Edelbrock AVS2. I enjoyed talking with the Federal Mogul rep (who owned Edelbrock then) about bringing back the AVS. Another carb I own but sadly haven't run yet is the Holley Street Demon with the plastic center because it reminds of the Thermoquad. I believe it will be a great carb as it has the same Thermoquad configuration of a throttle blade lower, plastic center and float/choke top.
mayhem
Well-Known Member
"...todays fuels are not friendly to todays fuels..." What?
Thanks, I corrected it "
Was in a hurry, should have said, "Todays fuels are not friendly to carburetors", I'll add heat as well which is why I suggested blocking off the crossovers at the cylinder head.
If using an aluminum intake with no crossover and the passages ae left open they will still heat the manifold which will transfer to the carburetor.
if one has a larger air cleaner like a dual snorkel size? It will trap the heat radiating off the manifold and raise fuel temps. If your fuel line happens to run through that area it increases the chances for problems.
In a few stubborn cases I've had to actually make an aluminum plate to block the heat radiating off the crossover area to cure the vapor lock issues the owner was having.
If one can access non - ethanol fuel (in older cars) that is STRONGLY encouraged as the ethanol will deteriorate fuel system components made prior to ~ 2010. Some of the early braided hoses will literally crumble. Accelerator pumps, hoses, fuel pump diaphragms are all
Another thing I forgot to mention is the Edelbrock carbs have had a tendency to percolate fuel on a hot day. This is a well known problem. I do not know if they've corrected it yet or not (my guess is not).
I like using phenolic spacers between the carb and manifold on any setup.
hope my ramblings are helpful to some .
"Was in a hurry, should have said, "Todays fuels are not friendly to carburetors", I'll add heat as well which is why I suggested blocking off the crossovers at the cylinder head.
If using an aluminum intake with no crossover and the passages ae left open they will still heat the manifold which will transfer to the carburetor.
if one has a larger air cleaner like a dual snorkel size? It will trap the heat radiating off the manifold and raise fuel temps. If your fuel line happens to run through that area it increases the chances for problems.
In a few stubborn cases I've had to actually make an aluminum plate to block the heat radiating off the crossover area to cure the vapor lock issues the owner was having.
If one can access non - ethanol fuel (in older cars) that is STRONGLY encouraged as the ethanol will deteriorate fuel system components made prior to ~ 2010. Some of the early braided hoses will literally crumble. Accelerator pumps, hoses, fuel pump diaphragms are all
Another thing I forgot to mention is the Edelbrock carbs have had a tendency to percolate fuel on a hot day. This is a well known problem. I do not know if they've corrected it yet or not (my guess is not).
I like using phenolic spacers between the carb and manifold on any setup.
hope my ramblings are helpful to some .
Xcudame
Well-Known Member
I like using phenolic center carbs ( Thermoquads)!
AJS1959
New Member
I put an Edelbrock AVS2 650 on my 73 Challenger 340 last fall. It worked great right out of the box. It runs smoothly and starts easily. Highly recommended.
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