396 rochester carb

[mikewarme]

I bought a rebuilt carb for my 396 a year ago. Finally got around to getting the truck running after paint etc. The carb is bad due to a crack in the body where the plugs for the primary jets are. Rather than getting another one thats the same , does anybody object to using say a 75 rochester that fit a 350 or 400 cu? My concern is that the 400 was a small block and even though the carb mounts will it perform fine? Otherwise im going to just order the correct one from Classic industries for a 69 like it came with. I want economy more than performance. Mileage is a factor here
Mike