6=8 and bore over?

A 71 Demon is a desirable car.
An LS swap makes it not desirable.
Much easier to stay all Mopar anyway, the junk bolts right in.

Re your roadability....front end components have to be in good shape before anything. I used the Moog problem solver offset upper control arm bushings in mine (installed to maximize caster) and had it aligned with 2 degrees positive caster. Do not use the old listed alignment specs. The car, with radials, tracks down the road hands off like a freight train. If you have bias ply tires there's no hope.