ive got a 91 305 tpi converted from a tbi. i traded out the serpentine set up for an alternator and power steering bracket set up. i didn't have a/c or smog and wanted to clean up the engine. i switched out the reverse water pump for one from an 86 and used the alternator. my problem is with the power steering mount.
i tried to use the power steering unit from the 91 but it will not line up with the install kit. the same goes for the the 86 power steering pump. either the unit is not clocked in the right direction or the bolt on the back will not line up to the new bracket. i could use the original brackets but don't want to if i can avoid it. the kit i got says it will work on power steering pumps from 69 to 73 and other sbc using long water pump.
will a pump from 69-73 work on my car? i know ill have to get the correct keyway pulley.

 

I don't know about year-to-year fit compatibility of GM PS pumps. Someone else probably has better info than I do. But IIRC, two other issues with GM PS pumps are:

1. Getting a pulley that will work with the pump shaft and belt arrangement you have (some shafts are keyed and some are press fit).

2. Another thing is the fittings. The early pumps are SAE and the later ones are metric. Your '91 should have a steering box with metric fittings. I don't think they make an off-the-shelf pressure hose with one end metric and the other SAE. Maybe an adapter is available or you can have a custom hose made.

 

I got it worked out. I relocated the rear bolt from top to bottom.