what bellhousing does the gas engine use in the '80s and on f600/f700 trucks with auto trans ? is it a sae standard 2 or 3

 

Those would be 370 and 429 motors. Not SAE patterns, but the same pattern as the Ford car and light truck 429/460 motors. From what I can gather, they used an adapter plate to mate those engines to SAE patterned Allison transmissions. I can't find any specifics doing a search, other than the reference to the plates. I can't find a plate, for example. A school bus with a 370 and an automatic would be a likely suspect for a plate according to one source.