Will bolt up to your 55 bellhousing-but you need to compare the input shaft/splines to your original trans and make it the same.
You can get an adaptor from Buffalo Ent, but not totally necessary, adaptor takes up the space you'de need to trim off the longer T-5 input shaft and the spline length problem goes away also. Clutch disc. needs to be same as your old one, but the T-5 has different splines, that's the rub, stock pressure plate is fine. Drive shaft/trans yoke needs to be late model, I used the one off my old Saginaw 4speed, these are common so no problem Also get over to Inliners.org website ane read their tips also. good luck