You might look into the Dart SHP block and build a 363 cid engine using one of their blocks as you can buy thier 302 block with a 4.125 bore.
If you need a block and rotator let me know as we are a dealer for Dart and Callies crank Co.
Here is a link to look over
http://www.dartheadstv.com/featured_...php?reset=true
Good luck which ever way you go