start with a megablock if possible, and a stroker crank 4,25" with small journal chevy rods and small pins.

You can build a 540 that way, or something a bit smaller if you decide not to max out the bore on the block.

Get some stage V cnc ported stock replacement heads.

Stock vanke ported intake manifold or a stage V dual inlive intake.

dual edelbrock carbs.

10,5: compression.

You can achieve what you want with a solid flat tappet cam, or maybe if you can go for a mild roller.