GM 14bolt. As far as I know they were all "normal" length, or at least the ones I have seen. I have an '82 C-20 and a friend has a '75 C-20, both are the same in "length" from what I remember. And they stuck our from the wheels about 2"
307 was optional only one year for the 20 series - 1973. For the 292 Inline6, it was optional for 20 series from 73-86.
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Chris Lucas
1973 Chevy C-10
1975 Chevy Silverado
Captkaos' Page
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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