Looking at picking up a 1981 w250 without motor. Transmission is in it, but bell housing and clutch set up is gone. Originally at 318 truck. I've got a good running 5.9 mag out of a 1997 truck that was an auto. If this swap is feasible, I'm ditching the injection and going to a carb and electronic ignition. My question comes when talking flywheels and clutches. Do I need the magnum flywheel and LA style
Clutch? Thanks for any help

I did this same swap in my 86 W250. You need a LA bellhousing and clutch and a 5.9 Magnum flywheel for proper balance. LA 360 and Mag 360s are not balanced the same. You are also gonna need an electric fuel pump for the Magnum engine. Also, the LA accesory brackets wont fit properly on the magnum heads. I would use the mag serpentine setup for the accessories. You may have to custom fab some a/c lines like I did for the A/C to work with the mag compressor but in the end it is a much cleaner set-up.

That is the answer I was hoping for, pretty straight forward!! Thanks