I've built up several 390 HP engines and just completed one done like this:
390 block bored to 428 std. , sonic tested with all cyl. wall specs meet.
72 cc edlbk heads, mild polish and port with
oil mods done. Ferara valves.
390 rods, shotpeened, ARP 190,000 psi rod bolts.
Comp cams 280, hyd. cam, pusrods.
Harland sharp roller rockers( Spend the money here! Buy direct, the edlbk heads have the valves on a slight offset and harland bolts on right the frst time)
428 crank shaft
speed pro forged pistons, 428 std., (you can run uo to 11:1 comp. with no detonation on 93 octane pump fuel)
Holley 750 cfm or Speed Demon 750 ( Dyno showed aprox 18 hp more with the Demon)
Canton
oil pan
Precision
oil pump, Modesto CA(only pump and shaft to use!)
This motor will give up 425 hp + or - @ 4800 rpms, and about the same in torque. $$$? depends on how much work you do do on your own ...aprox 4,500.00 Good luck
MD