[Lugnutz65]

You might need to custom fabricate your if the top of the radiator has a different thickness than the original Harrison radiator.

The original top support has 2 U shaped brackets with rubber inserts. These are spot welded to a flat plate with the proper bends. You could make one up easily enough if you have a metal brake and a welder.

True, buying a salvage part would be easier.

The pic below are for reference and should be correct for a 1960-1966 C10 with a short-wide V8 radiator and the last photo is for a tall-narrow L6 radiator.