`86 4+4 body on a `79 frame?

[vmax]

hello, i have a cab and bed off a `86 donor truck.
my question is will that body fit on a `79 3/4 ton 4+4?
also will the `86 core support and `86 fenders work on the `79 frame?
sorry for all the questions but i found a good deal on this `79 3/4 ton 4+4 and i always wanted a 3/4 ton.
my other question is if i use my `86 cab on the `79 can i use a `79 style core support and a`79 fenders? and `79 doors?
will the `86 bed lines match with the `79 doors?
sorry guys for all the questions i just need some advice.
thanx,vmax