parts swapout help

[k2c1959]

i am just starting resto on a 67 c10 shortbed stepside what i was wondering is if anyone has every attempted or if it will fit, i have a donor van that is a c20 1981, and im wondering if the crossmember and steering column and maybe rearend will work under this 67. i had the van given to me with a good 305 4bbl motor and transmission in it and would like to use all parts possible, if anyone knows whether they will fit.... i really dont want to do alot of modification to make them fit. and if the frontend crossmember will work, when i go to buy lowering springs, do i get them for a 81 or a 67? all help would be appreciated as i have never really attempted a frame up resto before and am anxious to get started.