I will have to look to see if I still have the part number for the base. I know I bought it from Summit Racing, and it was a standard base to fit Holley 2 or 4 bbls., and had a 14" O.D..
No idea why I can't post pictures here anymore.
BTW, we discussed this about 3 years ago:
https://6066gmcclub.com/showthread.php?t=50095