i imagine any 383 will fit, but I think I do remember something about a machining mod that the factory did to the drivers side engine mount area on 383 cars.
I have heard the same that the engine is mounted from the left front corner, sure someone with real information can assist. I have a 413 out of a 65 300 with the provisions for this mount style, interesting enough the 413 is a 68 date code warranty block! I can take pics of the mount if you need.
