I'm tired of the crappy rebuilt 2bbl carb from O'Reilly. I'm looking at the 2bbl 500cfm Demon 'Street Demon' from Jegs. Anyone know anything about them?
The Holley list 4412 500 cfm is a good replacement for the Motorcraft carb. I've used several over the last thirty years. Best carb Holley ever made. 4 bbl performance in a 2 bbl carb. Great bolt on swap for the 2 bbl and those on tight budgets. It is not equal to a 1000 cfm dominator, it's exactly half a 750 cfm double pumper, Holley rates the flow on a 2 bbl differently from a 4 bbl. This is due to the different vacuum pull on 2 bbls vs 4.
Holley also lists a 350 cfm 2 bbl as well, it's more of a stock replacement type though and not oriented toward performance like the 500 cfm carb. The 350 is list # 7448.
The Autolite's were never close to 500 cfm ratings. They came in sizes from around 190cfm to 465 cfm. The throttle bore size is cast into the fuel bowl on the driver's side, behind the accellerator pump rod. the smallest was .98, the largest was a 1.33. Other numbers I know of were 1.08, 1.12, 1.14, 1.21, 1.23. The 1.33 is probably the rarest and was used on the 2 bbl version of the 429.