1972 Plymouth 340 - 4 speed - 355 gear - Carburetor Suggestions
The AVS and AFB choices require an intake change or spacer. Maybe a creative gasket stack up will work too but I have never done that.
When I swapped on a old Federal-Mougal Competition carb it bolted right on without any issues including the egr on the intake. A thick fiber gasket is advised to combat heat and boiling the fuel in the bowl. It’s really weird to here fuel percolate like a coffee pot.
I believe the TQ is 800 cfm ?
There are two sizes to the OE TQ which are given a moniker or big and small due the primary sizes or ether 1.38 or 1.5. Typically given the cfm ratings of 800 & 850.
There actual flow rate is less. We did have a fella here (God rest his sole) that claimed he had the actual ratings which fell in the 737 or 787 ish, IIRC area. Then there are the 3 other TQ’s. The small over the counter QJ replacement with both Chrysler and GM throttle arms and electric chokes and two race versions at what is claimed as true 800 & 1,000 cfm. Both of these came with 2 part numbers each. They meter the air & fuel like the first year TQ.
IMO, there are 4 carbs I’d call entry level and good replacements.
Edelbrock’s AVS II carb
Holley’s 4010/4011 series carb
Holley’s Demon TQ like carb
Then there is the standard Holley 4160/4150 which is perfectly fine as well as there a well established carb.
MoPar guys are most familiar with what came on top, the Carter carbs which make a recommendation of the Edelbrock carbs very easy to do. There rock steady reliable. Jet, set it, forget it, your good to go. A once in a while cleaning of the air passages on top of the boosters is all that is needed.