My project is an '84 Jimmy. I removed the axles from a 1984 chevy 3/4 ton which are a 12" sf and 10" corporate front. 4.11 gears. i stabbed a 400 sm block with a th400 trans and 208. (in place of a 305/th350/208) I figured i would need some driveline work to finish the job and it was not until yesturday i crawled under the jimmy and to my surprise, the original driveshafts will fit. I thought I would have to lengthen the fron and shorten the rear. ??