TH400 shaft is shorter than the other transmissions for the same wheelbase. I'll have to check when near my books, but from memory the closest for a 4L60/TH700 will be a HJ to HZ TH400 shaft from wagon, Statesman, ute or van with the front yoke replaced with a 1-tonner yoke as these have the bigger front uni to match to the TH400 shaft but use the same splines as a TH700. I don't think it is an exact correct length though.