Duster Engine Swap

To simplify things, mopar engines belong in mopars.
If you want a chev engine, get a G.M. vehicle to put it in.
It's not worth the hassle to convert.
Period.
Don't bastardize vehicles, you will regret it and everyone will hate you for it.
Now get yourself a Nova and build a screamin' sbc for it, you won't regret it.
I think that's what you want anyway.