another 360/408 over heating

It would really be interesting to see this car go back to the way it came from the factory, cooling wise.
Nice 22" radiator, stock 7 blade fan, 180 thermostat, wire in the bottom radiator hose. 12/34 timming, correct A/F ratio. Simple factory stuff that even cooled an Elephant. If this didnt keep your 408 cool, then something is wrong with your motor internally.

Sure, its hot rodding, but this mad scientist car building has you exactly where you don't want to be. Go back to the basics.