I've never built an OK car kit or any other make of aluminum car. I pretty much work with just styrene but there shouldn't be much difference in mounting the trucks. Does the OK car have a wood floor?
Possible bolsters are from an American Lightweight kit or a CZ bolster from Atlas (which you have to order directly from their spare parts website). Scale City may have a cast metal bolster also. The picture below shows an ALW (black) and an Atlas (gray).
You may have to put a shim between the bolster and the car floor to get the ride height correct. My cars measure 3 11/32" (scale 13' 6" ) from the top of the railhead to the top of the car. I have several extra sets of these ALW bolsters and can send you a pair if you want to try to adapt them to the Atlas trucks. Obviously the Atlas bolster will work with the Atlas truck.
I'm using the lobster claw, truck mounted couplers on my cars. IMHO being truck mounted they work smoother on O72 curves than body mounted Kadees. The big claws are mostly hidden under the diaphragms so the visual impact isn't terrible. Kadee's will work if properly mounted however they do not play well with S curves. I wish someone would come up with adapters to truck mount the Kadees.
Ken
