1972 c-50 4+2

[7mty2C50]

hello im a new owner of a 72 c50 350/4spd split. im wanting to learn all i can about this truck . the crazy location of the brake vac booster . the hi/lo rear diff. are there any repair manuals out there for it or people willing to share the wisdom learned . another important thing is the lock ring rims 7x20 can i go to 19.5 or 22.5 ??? any way im here for knowledge . thanks all .