Go to Fordstrokers.com and contact Woody. Top notch service and products. They deal from street vehicles to 7 second race cars. Save up your money and do it right once. If the motor is cooked then best to start from scratch. If it is just eating oil then most likely the rings are bad but once you go inside you will find that is will need a complete rebuild. Then you need to find a machine shop that can actually be trusted etc. Then selecting the right parts is not for someone inexperienced or one is not Ford dedicated. All said and done you are better off buying a pre-engineered kit that will work right out of the box. Trust me I have spent STUPID money thinking I knew better.
You are only truly wise when you realize how dumb you are.
Your engine likely needs a rebuild with a .030 overbore, and new pistons which use a 5/64th piston ring instead of those damned metric low tension rings. If you elect to buy a long-block, make sure it has forged or hypereutectic pistons and not cast pistons. You could get a short block and throw some aftermarket aluminum heads on the short block....
Oil could be leaking from a head gasket so the engine isn't "blown". Or it could be a warped head. If the engine isn't turning over then it would be considered blown. If you want to replace your engine you can get the 302 (5.0 litre) or you can get a 4.6 litre. The 4.6 replaced the 5.0 in Mustang GTs.