The crossover allows exhaust heat to warm the manifold & fuel charge for fast warmups in cold weather. It's not needed for normal driving. The blockoff plates allow you to prevent the heating of the manifold, for increased power. A cold manifold = power, a hot manifold = economy.

The valley pan prevents oil from coking on the underside of the hot manifold. The burnt/coked oil is a contaminant in your motor oil, and can cause premature engine failure. If you eliminate the valley pan, you MUST use the blockoff plates to prevent the manifold from getting hot enough to coke the oil. If you use the valley pan, then you can use the blockoff plates or not.

 

When putting in the valley pan. Do I put a bead of Pro Seal on the heads, install the pan and the a bead around the top side of the pan as well, for the manifold to seal?

 

No, you do not need any sealant on the Valley Pan. The pan is made to seal the intake manifold.