I just built a muffler for my friends 2.9 '91 Ranger. 1/4" oil well casing, about 5 inches long and 9 inches tall. single 2 1/2" in, dual 2 1/4" out. Dual chambered, and one wing-plate baffle. Very strange looking muffler.
He got it put on today, started back from where the cat was deleted with 2 1/2" pipe. The muffler was hung right behind the cab, right under the up-most part of the bed. The 2 1/4" duals side exit under the frame and spring hanger in front of the passenger side wheel side by side. They then turn 60* degrees up, and tilt backwards slightly towards the wheel, and run up the side of the bed about 8-inches.
It sounds completly insane. Its deep as hell, thumps at idle, and does not buzz or become ricey no matter what the RPM. However, rolling up the passenger side window completly eliminates the exhaust note. So its not annoying at all.
I took a shitty cell phone video, I will see if I can get it uploaded.