I really need some advice here

The cars *** coming out from under you and getting in front of you is a suspension traction issue. Not a HP/torque issue.

My advice is build the 1991 "LA" roller block and upgrade the heads later. Ported 308's are fine. And since your doing that work, cheap! Building a Magnum engine limits your heads to Magnum only heads. The problem is the lack of a block oil passage for the more common "LA" head.