Welcome
As far as what to do.........
What do you want it to do?
Street driving only? Around town or road trips?
A little or a lot of autocross?
Possible track use?
Realistically where will 80+% of the mileage/usage be?
You didn't mention one critical element of a build that a big block and T56 will exploit - Brakes!
Build the car according to your realistic usage, that will help establish a priority list and budget.