Why is my 350 running warm?

okay i had a stock 350 in my 85 chevy truck and the harmonic balancer bolt back out and messed up the crank but i put another 350 in it but this one has a mild cam edelbrock intake im using the same radiator water pump and everything but it is running warm cruising down the hwy it runs about 210 i took the thermostat out and it still runs at about 210 i flush the motor and radiator but still no results so im stumped i put a new fan clutch on it also. but could someone help me? the motor is a 78 model if that has anything to do with anything