[RedHawk]

I guess the question is does your overheating happen on highway or at 40 mph or under?

If its under 40 then I bet its your fan as it was with mine. Having the same setup as you I found out that the fan was wired inccorectly and the blades were rotating in the wrong direction essentially pulling hot air from engine and blowing it into the radiator. Once we identified this and properly wired the fan the temps have never climbed over 200.
Not saying its a improperly wired fan but it could be that your fan is not coming on while running properly at slower speeds or its not running enough cfms to cool coolant.
....or as mentioned above and more
Bad thermostat
Bad alternator not powering the fan
Bad fan or inadequate fan
Or need better radiator combo
Or dirty or rusted radiator coolant causing blockage
Wrong timing
Carb too rich or too lean-inspect plugs
Bad guage
Bad sending unit
Oversized pulleys running water pump to slow
Bad water pump
Air in coolant-need burp
Hose pinching
Over flow tank
Heat soak? Just threw that in. Need carb spacer
Ground cable somewhere is loose.

Hell I dont know, lol.