What about destroking/sleeving a 383/400 with Max-Wedge heads? Custom/welded intakes allowed?
We tried that before the de-stroked Hemi. 361 block. 348 cubic inches, port matched maxwedge heads, single 4 bbl. Ran it way past 8500. 4 speed. I think you would be hard pressed to get close to Hemi power even with state of the art raised port maxies.
Valve train would be easier to sort out on a wedge.