Hello I'm having some issues on if I should buy a transmission out of a 91 w150 with a 318 4 speed auto for my 91 w250 with 360 4 speed auto just want to make sure it's right for my truck

 

Likely the same trans, problem becomes, balancing. The 318 is internally balanced, so, the flexplate and torque converter are neutral balance. The 360 is external balance, so, there are weights on either the flexplate, or the torque converter. If the weights are on the torque converter, you are going to have to buy a new one, re-using the old one out of a bad transmission will simply destroy the new trans in relatively short order.