Overheating 360 new engine

Two thoughts come to mind:
Is the Sniper controlling the timing or do you have it manually set? If manually set, could be too much initial.
You have a March pulley system, but is it the right ratio? You should be at about 1.3:1, WP to crank.
The timing is not controlled by the sniper set up. As far as the March system Im not sure. I just ordered the kit from them. I figured they would sell me the proper one. (Their i go thinking)