I was reading Holley's instructions for their LS swap crossmember kit for 73-up C10's and it mentions finding the centerline between the framerails, and then offsetting the transmission output centerline 1/16" to the passenger side of the vehicle for the final mounting location (see last page).
http://documents.holley.com/199r10760rev1.pdf
I have a '72, but have been doing some research on this and have seen that on many GM vehicles the engine centerline is offset toward the passenger side. Does anyone know if this is the case with the 67-72's? Just want to be sure everything is squared up once I do my swap and was curious if anyone has bothered to do this offsetting for their swap.