Firedude,
Here are some specs to chomp on from J. D. previous investigation:
Walker#
21468 6x22. 5 case, 29. 5" long, 3" in/out
21471 7x28. 5 case, 35. 5" long, 4" in/out
22572 9x20. 5 case, 27. 5" long, 4" in/out
On my 98, I put the 22572. The body diameter is just a bit to big for a perfect fit, and will contact frame components with a gutted cat in place too. You can fab it in anywhere in line if you remove the cat altogether. If you want to keep the cat and put the muffler on behind and want the 21468, you can use an adapter to go from the cat 4" to muffler 3" using Walker# 41563 reducer.
Hope this helps,
Steve.
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98 qc, 12V, 4x4, slt laramie, 3:54 ls diff, 2YG pkg, Kelsey trailer brake control, dodge running boards, diamond plate bed rails, prime designs bug shields, silencer ring wind chime on porch, Raven cab-hi camper shell, psychotty air system, T/C lock-up switch, gutted cat, Walker muffler 22572, crome 5" tip from Kenworth stack, Isspro guages, A pillar 3 guage mount, TST #6 250/635.
Toys: 70' F250 4x4 highboy- 429cid 400+ hp on 35"BFG's(ranch truck) 64' MF 205 tractor 3cyl perkins diesel w/bucket