Funny I just subscribed to a post of a guy on this site who's planning on putting a Hellcat motor into his 72' Demon.
2018 Dodge Challenger SRT Hellcat weighs in at 4456 lbs.
My 74' Duster weighed in at about 3,200, I imagine that Demon is roughly the same weight.
That being said I'm currently putting together a 408 stroker, I do have Eddy magnum performer heads still in the box, I'm going to take them to a local shop here to get them "worked" over.