Slant Six Saginaw Keyed and Nutted Pulley

I called 440 Source and they said the Saginaw pulley they have that is keyed won't work with a slant six. They said belt alignment will be off. I'm trying to find something to use on the pump that Peter Bergman sells for use with the Borgeson gearbox. The pump is rated for 1200-1350 PSI with a 2.7-3.5 GPM Flow Rate. Is there a pump with pressure settings close to that for a V8 that would fit the slant with the slant's brackets?