440 build need ideas

A stroker 383 or 400 will also be perfectly suitable for a 500-550hp build.
They made more 383’s than any other big block buy a huge margin...... so it “should” be reasonably easy to track one of those blocks down.

9.5-10:1cr, and a set of E-streets will easily get it done.
Cam choice would tied to the exhaust/gears/converter.

The aftermarket crank and rods to build the stroker will add to the cost though.