Could use some expert Demon handlers

Welcome to the site! There is a wealth of knowledge here.

I'm pretty sure some Demon's did originally come with a slant six ( just as the Dart Sports did ). If it is a clone, it probably was done off of a Dart Sport ( or a Duster, but then it should still be titled as a Plymouth Duster ).

If it is a real Demon, and in good condition it probably is well worth the $4k. If you could post pics of it, more people would be able to chime in with advice for you.

RTom