Help with radiator

Maybe I'm being over simplistic here but if you didn't have a problem before you put the new radiator in, but do now, then it seems to follow that the new radiator isn't functioning as advertised. Possibly the larger tubes are not slowing the coolant down enough to get the temps down.

Whatever the case, I would put the old radiator back in (if available) and verify that all is good (it was before the change) and move on from there. Dennis

Beautiful engine/ bay by the way.