Whatever your cousin decides to do, let him know that if he puts a V8 in it sooner or later, I will buy all the bolt on stuff off his inline 6.
I had an '81 SWB 4x4 once and it came stock with a 250 inline. Best truck I ever had. It got 18 mpg on the highway. Sold it to buy some big tires and rims.
I would love to find another SWB truck and put a 250 back in it. I can find the inline motors all over around here but not the brackets, accessories, etc.
I will buy all the stuff off his motor, the motor mounts, distributor, anything that he doesn't want. Just leave the motor as you guys are too far to pick it up.