later (or any) 390 block that will pass a sonic check to allow .075" overbore. I have sonic checked dozens of 390 blocks that will go .075".
install main studs
oil mods to block
off the shelf Ross 4.125" forged pistons (Doug at Precision
Oil Pumps can get them, and all the other parts you need for a good price.) 9.9 to 1 to 10.1 to 1 compression
Scat 4.125" stroke crank BBChevy rod journals
Scat 6.700" Rods BBChevy rod journals
Speed Pro or Sealed Power moly rings for a 400 Chevy (4.125")
Hydraulic cam around 240 degree duration @.050", .570" to .580" lift, 110 lobe centers.
If you really want to rev the crap out of it
run a mechanical flat tappet with 255 to 260 deg @.050"
.620 or so lift should get you to 6200/6400 rpm.
If you want more, buy a 427
good roller rocker arm set (Erson, Crane, Precision
Oil Pumps, Harland Sharp, etc.)
Stage II ported Edelbrock heads (upgrade the valve springs)
Performer RPM intake
750 to 850 Holley Vacuum or DP
MSD billet Dist with timing set at 14 to 18 initial, 36 total.
442 cubic inches
idles at 850 rpm
runs great on pump gas
450 to 480 hp at 5800 rpm
Should be able to build this combo for 7 to 9 grand depending on who does the work.
HTH,
--Mike