Someone found the info at a site and seems like im on right track making the change the same way . I swapped the tail shaft and shifter plate from S10 to the Gt trans . The speedo is located in a different location . To make the speedo change i will measure the difference between gear and tail shaft and shim it to center . Then some good 2 part epoxy will hold it in its new position. Before i do this i will have to get the rear gear sizes im going to run to correct my speedo. But here is GT trans with a S10 tail shaft . The S10 rated at 250 ftlbs and the GT rated at 300 ftlbs look allmost identical on the inside .