Outer Limits 4x4 Board

i had a 1hdt and auto fitted by my mates about a year and a half ago and now the heads gone so im going to pull it and replace the rear main seal while im at it so the question is can i bolt the old 2h back in or is the bolt pattern between the two diffrent

possibly different, what gearbox is behind it? could use a 2H/12HT auto A440 belhousing

im unsure it was a compleate package out of a 1994 80 series