[Gromit]

Here are a few photos and part numbers that might help; this is out of a SBC350 and 1970 C10 but should be the same mounting points in your 307 block of course.

I can only offer info about the pump/pulley/brackets for now - the actual power steering hydraulic recirculating ball unit that attaches to the steering column is a bridge too far for me at the moment - I know nothing about it except the number cast into mine which is 7802642 and that it is so heavy duty it looks like it would be right at home steering a battle tank.

The pump pulley is stamped GM and number 3925537 DC

This is with the 8" damper and it is an A/C truck

There are two brackets that bolt together to hold the pump to the block and provide a means to adjust v-belt tension.

The larger ductile iron bracket has a GM number cast into it: 3957466

The smaller steel bracket has no identifying numbers on it.

Photos attached..

Regarding my earlier comment about the engine mount bolt being hard to get to - upon closer inspection if you disassemble the two parts of the bracket and remove them from the pump body it is then easy to get to that bolt - however I have not yet tried to reassemble everything so we'll see how it goes..