It all depends on your budget and how far you want to go with it..
If you're shooting for more than 500 WHP, it'd be a good idea to start off with an aftermarket block..
I used to run a DSS 331 bottom end, ran it for 3 years with zero problems.. my goal was SC but lost my job and went back to school.. Sold the car to move to CA
Anyhow - Are you looking for a flat out drag car? A fun street car?
What sort of shape is the notchback in?