Pulley Troubles....

I THOUGHT I had posted a thread about this, but I guess I was dreamin. Anyway, 77 400, 906 heads, 67-74 Alternator brackets like this:

1967-1974 Dodge Challenger Parts | MD2427 | 1967-74 Mopar Big Block W/O AC Alternator Bracket Set | Classic Industries

I've gotten a couple of pulley sets and they've both not worked.....or at least the water pump pulleys have not. The trouble is, they hit the water pump before they bottom out on the water pump flange. Does anybody know what I need? Thank you drive through.