Hi Mike,

Some people use stacks of washers as spacers. I buy a 1/4" pipe nipple from the plumbing aisle and cut it to length.

The outer groove on the compressor pulley lines up with the crank pulley, so your ps pump pulley needs to move forward to that position, about 17 mm.

Looking at the photo there are 3 spacers. Both the one on the far left and the one on the far right are 17 mm. The shorter one between the bracket arms is whatever will fit snugly in there. It depends on the type and spacing of the bushings. If you're replacing bushings, measure after they're replaced.

There is one more spacer not shown that is used to keep the adjuster unit in line with the pump. I think it's around 12 mm, but it's not that critical. whatever looks good.

You'll need a 5" long 5/16" or 8 mm bolt and nut, and a bit longer bolt at the adjuster hold down.

The belt I've been using is D&D power drive 15417

https://www.ebay.com/itm/111963724643?ViewItem=&item=111963724643

That should get you started, but there might be some fine tuning if it's not where you want it, and I can't say if there's any advantage to using poly bushings. Mine have been fine with rubber.

Peter