i believe you can swap the input shaft from a '96-up R150F into an R151F. that'd give you the longer input shaft you need, a lower 1st gear and 23 spline output that'll mate right to a toyota gear driven case(as long as it's 23 spline as well, you can swap that input shaft in)
i think you just need the AX15-4.0 bellhousing from a jeep and you can probably use AX15 clutch parts
