A few comments... . The PS pump pulley location/spacing can be different SB to BB. Also, best to stick to a consistent year/style on any pulley setup. Bouchillon has re-pop brackets that work fine as long as year/style is consistent. May be the same thing Mancini sells. I think the Bouchillon brackets - which I use on a 318 to BB swap - are early 70's BB style.

After some problems mixing and matching SB and BB pulleys on my stuff I adjusted. Early 70's BB style from Bouchillon for the PS bracket and fan pulley. I also had the PS pump from my '78 400 BB core engine rebuilt and re-used it.

If you can find the "nut" style Saginaw SB pump, Bouchillon sells a pulley adaptor/spacer to use it in a BB application.