Good, you are within the 5 HP per foot rule.
Check the easiest things first:
Bad temp gauge giving a false reading, check temp with another thermometer in the radiator or with a IR temp gun.
Oil in the coolant or coolant in the crankcase oil.....blown head gasket.
Are the radiators fins clean of seed, chaff? Look deep into the radiator.
T-stat working? With the engine running and warmed up you should see coolant circulate with the radiator cap off as the T-stat opens and closes.
The lower radiator hose should have a spring built into it. The spring keeps the hose from collapsing and chocking off the coolant flow.
Bad/worn out pump.