I have a 1970 C50 that I am building into a dump truck. The cab has a few body issues I am going to work out, otherwise a nice Colorado truck. One of the problems is that the truck originally came with a 292 six and now has a 75' 454 light truck motor. They (the installer) hammered the firewall for valve cover clearance on the drivers side, plus they cut a hole elongating the clutch rod. Anyway, what I think they did is took the six out and bolted the eight in place as they home made the front motor mount out of angle iron.
I am getting the correct motor mount and starting front to back. I see on the frame rails, that there is about four choices for trans cross member locations. It looks like the differences are about 2 inches between holes.
Does anyone know if the transmission was located farther back for the six versus the eight in the C50-60-70 series trucks? The only problem I seen then is the shifter might hit the dash and the hole in the tunnel will not be right? Again, were the V-8 trucks different?
Any help would be appreciated,
BaconFarms
1948 GMC 2 Ton 1958 GMC 370-8 1965 GMC 5000 1970 Chevrolet C50
welcome to t he site. As far as I know, as 3B said, the trans location did not change. I don't have any newer trucks but, my understanding is that the change was the engine mount location. This has been my finding on most of the cars and trucks that I have worked on over the years. The auto manufacturers want to change tooling as few times as possible so, they will try to use as many of the same parts and assemblies across the different optioned vehicles as possible. AS you said, a change in trans location would change the hole in the floor, then also clutch linkage, driveshaft length, possible park brake linkage, and probably a number of other things I am forgetting about.
