[Mike C]

Yup. I looked pretty closely at my truck, and it seems you could use a 3 1/2" hole saw to cut through the center bearing crossmember (or 4" if you need more clearance), then weld a 2" long by 1/4" wall piece of 3 1/2" pipe in the hole. Then 2 1/2" exhaust could be run through the crossmember with 1/4" clearance on either side. Might be a little tight, so go with the 4". That way you can keep the pipes between the frame rails at least past the back of the trans. The trailing arms are a different story however. Leaf spring rear makes it a LOT easier to do exhaust.