My 360 is overheating.....

I have a 74 Duster with a 360 very mild cam edelbrock performer intake and Holley 750 carb with pertronix billet flamethrower distributor...As soon as I start it the temp starts climbing..I pulled thermostat and with radiator cap off I can see flow through the radiator and water pump isn't wobbly...no matter what I do it keeps climbing....is there a possibility of it not getting through passages in the motor...