This looks fairly complete. Includes the Pierce governor, auxiliary kick-down cylinder, and the unloader pistons on the cylinder head. (also the inlet air filters which are nice but these obviously challenged.)
3 bolt waterpumps can be bought.
Does it have the unloader valve? (this is a brass valve and has a spring which you can move on a lever arm to have different pressure settings.)
Unloaders are available new (different appearance but same function) from the original unit manufacturer Conrader at Grainger.
Bump on this.
Joe K