Gasket ?
 

I have a gen 6 502 Felpro recommended there 1071 gasket. My question is - I am rerouting the water flow to, from the pump into the front water crossover pipe through the block and heads and out the back of the intake both sides of the distributor to the tailpipes. Do I have to address the head gaskets for this change?

Felpro #17048 is the right one for your application.