The GMC CCKW

No matter what you use for a muffler on your CCKW or Chevrolet 4X4, try to fabricate some sort of Tailpipe with a bend and sufficient length to get the exhaust at least a few inches outside the frame rail. Something about the aerodynamics of the truck bodies that will draw the fumes along the bottom of the body and it does into your cab. I have witnessed drivers in convoys get sick when they have a missing pipe or blown muffler.
Joel

I have copies of an NOS tail pipe for sale if someone needs them.