well....depends on your definition of a small-block....

you're looking aftermarket block for strength.....

a P5 head probably has more raw HP potential than any W7/8/9,
but there, you're talking very little in common with a factory SBM, save maybe bore centers.

bar none, the latest 5.7/6.1 hemi package has the most potential power of any stock "small block mopar" layout. they share bore spacing, bore, stroke, & main bearing size with older LA motors, and could be lumped into the "small block" category just as easily as a P5 engine or even a 48 degree W7/8/9 motor...

realistically the OEM 6.1 heads, max ported, have as much raw flow potential as a W7/8/9, plus the added benefit of no valve shrouding due to the valves opening up away from the bore...