Alternator brackets Q? .. Difference in dimension

[BumpaD_Z28]

So I'm fighting an Alternator belt squeal at upper RPM's (about 4600-5400 redline) on my BBC in a 1967 Camaro. Alternator is mounted top of passenger side head (69+ style NOT 67 location), with a CHEAP chrome bracket on top, and the factory mounts for the rest ...

I already have a tried a HUGE pulley on it (5") too slow it down and that didn't do the trick ...

Question is between these too aftermarket brackets there is a 3/32" rear spacers dimension difference ???

.. I'm thinking that the MARCH one would put my belt "slightly" more inline as it look just barely too far forward now

March:
http://www.marchperf.com/instruction...nstuctions.pdf

Billet Spec:
http://www.billetspecialties.com/assets/pdf/754.pdf

THOUGHTS ?

THANKS! ~DaVe