If you want a period correct engine, I can highly recommend Dwight Powell from just outside of Atlanta. He has a bunch of NOS 427 and 428 blocks and other parts and has been building primarily these engines since 1968, including for NASCAR (some of the 427 blocks supposedly were extra blocks bought from NASCAR shops years ago after they changed the rules). I will try to post some pics, but here is what he built for me:
-NOS 427 Block (D3AE-6010-AA, C8AZ-G-427-HP), standard bore and stroke
-Ford 427 forged steel crank, standard
-NOS LeMans rods
-NOS forged, small dome, FoMoCo/TRW
-NOS medium riser, C5AE-F
-Ferrea Racing 6000 Series Competition stainless steel valves
-Blue Thunder 1x4 medium riser
-Sealed Power moly rings
-Holman Moody Mechanical Flat Tappet, C5HA-6250, Custom Grind Cam, Lift .526, Lash .025, Rocker Ratio 1.76
-Cloyes double roller timing chain
-Holman Moody hollow lifters, solid shell type
-Melling high-volume
oil pump
-Holman Moody lightweight hardened push rods
-Harland Sharp roller rockers
-Holley 750 CFM four barrel, manual choke, vacuum secondary
-Assembly Balanced
-Compression ratio 11 to 1