i changed from a 350 to a 400 in a 73 jimmy years ago. the 400 was out of a 2 wheel drive like your talking about. i pulled the tail section, took tranny to a tranny shop to have the shaft changed. its not an end shaft, the front pump has to come off, the shaft runs full length of tranny. they only charged me $20, it took him about 15 minutes. i should ad i already had the shorter shaft.
