As far as I know, all TH400s with the chevrolet bellhousing bolt pattern came with a short tailshaft. The BOP TH400s were available with either long or short tailshafts. The trick would be to take a long shaft BOP TH400 and put the guts in a chevrolet case, so you could have a longshaft setup. This would shorten your driveshaft a couple inches and greatly help with
critical speed issues, since ...