Final update. I have it all in place now, and am happy with the pulley groove alignment.
Getting this all sorted was a lot more hassle than I expected. GM must have equipped millions of long water pump small blocks with both power steering and A/C. So getting everything to fit and line up is not cutting edge stuff, but should be very routine.
Here's what I came up with in the end:
- Saginaw pump for bolt-on pulley (Performance Online)
- Steering pump bracket kit for long water pump (Alan Grove Components, #402L)
- Aftermarket factory-spec 2-groove steering pump pulley (GM #3941107)
- Used factory 3-groove crank pulley (GM #3972180)
- Existing factory long water pump 2-groove pulley (standard early '80s GM part)
Even with all this, mostly factory parts, I had to re-engineer the pump mounting a bit. While AGC says their parts are designed to use factory pulleys, when I mounted the pump per directions, the groove alignment was not correct (too far forward by about ｽ a groove). Luckily, the design of the AGC brackets allowed me to substitute different spacers to move the pump back about 5/16". That made it all work.
I'm pleased with it all now, but it sure seemed to be a lot more difficult than it should have been.