Doors changed in 77 because of power motor mounting. That and they changed the size/mounting of the door panels.
73-76
77-91
Cabs change only in enhancements/improvements, no drastic departures from the norm.............in comparison to doors.
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Chris Lucas
1973 Chevy C-10
1978 GMC Jimmy (2WD) - SOLD
1987 R10 twin turbo LS
1991 R3500 SRW CrewCab
1985 K5 diesel swapped project
1989 K5 2WD conversion w/ Vette susp Project
Captkaos Customs
73-87chevytrucks.com