6-5 lug conversion and back spacing please

[250powerglide]

i have done a search and cant find what i need . the truck has been changed to 5 lug with parts fron performance on line . disc in front and axle swap in rear 1969 model . seems like i read that the axle conversion makes the wheels set i little closer in to the frame ? this summer i will be getting the coys c5 style wheels in 22'' and id rather them send the wrong parts then me order the wrong parts if you know what i mean . can you guys put it in stone for me ?