Anybody swapping out there 4 bbl for a 2bbl?

i think 2v or 4v carb doesnt make that much difference. i think change trans to overdrive trans is best way. ex 2004r 700r4 trans for gm car.
i got 59 el camino with 350 4v and 2004r. i get 22mpg.

 

FWIW, in the late 70s when they wanted to replace the 2GC, the big Rochester 4bbl primaries were so efficient, that became the new GM 2bbl carb, to the point that the first year or so is made with the same casting with the secondaries blanked and installed on a 4bbl intake. I saved one off a '77 LeSabre (Pontiac 301) just because it was wierd.

If your car has a big Rochester, it would be an easy swap that would look the same as a 4bbl as long as the air cleaner top is on -

I'm not sure, though, if they changed the casting to eliminate the big blank section before or after they went to computer controlled carbs about 1981.

 

Repeat to yourself, "Keep foot out of it".

 

My 48 panhead gets 50 mpg...obviously my 48 1/2 ton dosen't do quite as well. May put a blower on it and see if that helps.