Well that sucks. They can be welded, not sure if JB weld would hold it even temporarily.
The only bases that will even physically fit would be from 390 Holley 450-465 Holley 550 Holley The 550 Holley was used on lots of Ford trucks in the mid-1970s, decent chance of finding one at swap meets. The 390 Holley was used on International Harvester lots of years but still fairly rare. The 600 Holley has 1-9/16 throttles, not the same, I don't think they will interchange although they are dirt cheap of course. Some of the passages and the gasket are different too, have to make sure it all matches up.
