Carter AFB 3721SB for '63 Avanti R1?

[michaelb]

Sent off the carb from my '63 Avanti R1 to Dave Thiebaux for rebuilding assuming it was the Carter 3506s OEM carb.  TUrns out, it wasn't.   It's a Carter 3721SB  that was used primarily on Vette 327's in the early 60's.    Not certain why the previous owner made the swap.   I had driven the car for about a year before putting it on the lift recently for some brakework, with no fuel-related issues that I can recall. 

My question - what are the differences between this carb and the 3506s?  Am I setting myself up for future problems if I re-install it? 

BTW, an absolutely beautiful rebuild job by T-Bow!

[silverstude]

I believe the 3720  was the carb used on 65 Corvettes with a 300 HP 327.  The lesser HP 327's had an WCFB carb.  The service replacement for the 3720 was a 3721(s).  I can't find the CFM rating but the jet sizes are almost the same as a 3506, as is the CFM, which is around 630.

Edited September 21, 2021 by silverstude

[MARK]

The work Dave T does is beautiful. I have relied on him for years for parts, service, rebuilds and exchanges. Also an encyclopedia of information.

 

Mark