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.

That's exactly what we did for a friend's '68 Charger build. We used a 383 block and a cut-down steel 440 crank, 440 rods and Ross flat-top pistons. Edelbrock 76cc E-Streets with upgraded (dual 8005A Isky) springs and a Comp 306S Magnum .555" solid camshaft. He wasn't really a MoPar guy, he just loved the Charger, so I had him go big block and we used the 383 because it was basically free for the taking, and I had plenty of rods. A guy gave him the steel 440 crank from the trunk of a '74 Satellite he was crushing. You never know!!