You can do pretty much anything to a 3600 that you can to a 3100. The front halves of the frame are the same so the MII front end is not a problem. The rear half of the 3600 frame is narrower than the 3100 and of course longer.
The 3600 rear springs are hung outboard of the frame rails and the 3100 are hung underneath the frame rails. I recently saw a rodded 3600 with a low down in the weeds stance and it looked pretty cool with that long box.


Steve

'49 3800
'52 3600
'57 3100