Need info on 1961 Carb

Just a quick question if anyone knows. What 4 barrel carb came on the 1961 Electra 401 and what was its CFM rating. Thanks

 

Pretty sure it was the Carter 3503SA.

This was before CFM ratings, but it is about 500CFM.

 

Thanks truck monkey

 

I just used a chart and found the 3578 also to be 61-63 401 AT, I have about 6 Carter carb's that I was going to list in the For Sale section.
John

 

It could have come with either an AFB, which most Buick's were 625CFM's or a Rochchester 4GC which was about 525 CFM's.