Ok, I think I know the answer to this, but I figured I would ask. I have a 73 440, non-AC, with the smallish alternator bracket. I am going to be swapping to the early style water pump, an aluminum version from Mancini. Do I have to swap to the early style alternator bracket? I think the later one just uses different mounting holes or even the same ones, I can't recall. Thanks

I don't think there is any difference but with a bracket or pulley question, I look at Bouchillion's site or call them.

http://bouchillonperformance.com/BPEalternatorbracketkits.asp

there is a different hole , pre 67 . maybe 66 ? and later , Most of the aftermarket alum housing have both bosses , one is at the thermostat flange ... early ... , below it ... late ....

What side is your original water pump housing inlet on? I was doing some comparison recently between the later style pump housing ('73 and up?) and the early (late '60's/early '70's). The mounting holes are in the same location (as I would expect the Mancini one to be) but the boss thickness was different by up to 1/4" - which may or may not create alignment issues with existing brackets.