You can use the 390 heads and intake. The std 428's that came in the birds shared many of the same parts as the 390's. When your the heads back you'll see a casting number between the center 2 spark plugs ex: C6AE-6090-J. This number will decode the heads but they should work fine otherwise. Then you need to decide if the 428 needs to be a 66 casting or if any 428 will do. If your trying to numbers match the engine to the car this can be a painstaking process. But it can be done and you need to do your homework. If you just want a 428 it's pretty easy to find parts. Block, crank, pistons and flexplate are the basic items you'll need. You can reuse the 390 rods if you choose. They are the same as the 428's. All the rest is std rebuild items. You can even sell the 390 block,crank etc...to offset some of the costs.

G.