Mike has it right, however, there may be some internal changes to the metering due to changing emission control requirements. Ray
I would double check the CFM rating. I know 71-74 455 carbs on Buicks were all 800 CFM and I thought 350 carbs were the same. There were just internal passages that were different so they should not be switched. I do not know 350's however but this is worth checking. You can visually see the difference in 750 and 800 CFM carbs but looking into the primary barrels. You can see the bigger barrels quite easily when they are next to each other. If I am wrong on the 350 carbs please excuse the ignorance and set me straight.
