g73 318 LA Motor to be rebuild.

You can safely run the cast crank and Hyperutecic pistons. You can also use OOTB (prepped) aluminum heads. For a good head (IMO) for this set up, look at the ProMaxx CNC heads. A very good head well priced that flows 280 cfm.
(FWIW, a 50 hp spread in this power area is a lot of HP.)