Noob question about radiator ports

Are the inlet and outlet ports on a radiator dedicated or can you use either one as the outlet or the inlet?

I believe most if not all are bidirectional.

Some dual pass radiators have a recommended inlet. It really depends if the flow is running parallel or from side to side relative to the air flow direction. You would want the flow to pass the exhaust side of the radiator first coming back trough the intake side. I really doubt that there is much of a difference anyway. If you want to check for that you can measure the depth of the inlet/outlet chamber from the holes.

AFAIK, it doesn't matter unless a specific radiator is a dual pass is my guess as well.