The 250C is a junk light weight tranny,, the 3rd gear clutch drum only has 3 plates and disc in it if I remeber right,, I trashed one thinking it was a 350 turbo,, and of course the wife was driving it when it went,, so I swaped it out with a 350 turbo and tore the 250 apart,, to me anyway a big difference inside the two,, check with Mike at Mikes trannys as well,, Matty man