Carter AFB and Rochester 4GC

[Guest]

I've got a 64 Riviera with a Carter 3665S. I've got a chance

to pick up a 4053S and a Rochester 4GC (7024040, correct for 64 401)

for a good price. My questions are:

- Did any 64 Rivs come with a Rochester?

- Are there any reasons that I would or would not want

to make this switch?

- What is the difference between a 3665 and a 4053 (cfm, jets, etc.)?

- Can I install a 4053 in place of a 3665?

Thanks.

[NTX5467]

In general, AFBs of that vintage were configured similarly to the 4GCs, with respect to the way the secondaries were operated (with weighted auxiliary throttle plates above the main throttle plates in the secondaries). As for CFM ratings, that didn't come into play until the later '60s or so. Prior to that, carbs were rated by their "venturi area" (in square inches) with the orientation that more was better. If you compare the throttle bore sizes to later Holleys with CFM ratings, it would appear that many of the 4bbls in the '50s and '60s didn't quite break the 600CFM barrier whether due to venturi restictions or basic throttle bore/venturi sizing.

There might be more performance items for the AFBs for incognito enhancements as the current Edlebrock AFBs are built from the same basic blueprints as the originals. Meaning, metering rods and jets and power piston springs. The current AFBs that Federal Mogul sells are still the original designs, but began life as a Chevy 327 carb that has been upgraded with an electric choke and other things to make it more universal. You can also use these carbs to gauge the CFM of the earlier carbs also. Other than the polished appearance of the AFBs, I suspect they are still pretty close to the cosmetics of the earlier ones or could be made to look the part with a little work.

I believe the later version AFBs might have the dual bolt patterns (on the base plate) but with the larger air cleaner air horn (air cleaner mounting circle) that's "Holley size". These would be definite things to check for plus whether the carb is configured for the exhaust heat track in front of the primaries or not.

Make sure that all of the linkage for the ones you have found are all there and mostly correct for what you need. Other than that, it would be a judgment call of which one would be best for what you have.

Just some thoughts . . .

NTX5467

[rocketraider]

For reliability and parts and technical support, it's the Carter AFB or its derivatives hands down. 4GC have been obsolete for over 30 years and there are no parts other than gasket kits readily available. Not to mention they have their quirks. I have two of them on identical 1964 Oldsmobiles- one works perfectly, the other has given me fits for fifteen years.