I had same rad/fan problems on my 65 chevy2,,,my rad looked like the original type,,, got it from us radiator,,it was a super cool 3 core,,,what I found with 250 water pump and a 1/4" alum spacer(the savior) from march pulleys,,(it wasn't cheap,,,)put the spacer about 1" away from the core,then the fan and bolts,,anything less the blades smacked the damper,,2 grooves,,the original 1 groove cleared, the fan was another concern, I got a nylon flex to fit but the big one hit the tranny fittings and the small one too small,no flex fan fit all the arcs on the blades hit the damper, and steel ones with no flex didn't work either the front tips of the blades are out farther than the center hub,,it was way to close to the tanks for comfort,I found a universal steel at autozone that was flat across the face and fit,, I picked the larger to get side to side on the rad, but it did not allow use of the tranny fitting,, even with the tightest 90 I could find,,,
