you need a 38r non EBPV turbo for your 7.3. the stock EBPV restricts the exhaust very bad. as well as a 4 or 5" straight exhaust pipe, you will see drop of 150 to 200deg in egt. I run a 2003 7.3 6 speed manual trans, 4.11 gears 32" tires, dual disk clutch, AC code injectors, regulated return fuel system, 38r turbo straight 4" turbo back, AFR Intake, diesel innovations tunes and i absolutly love it. been pulling heavy for 10 years straight without missing a beat. yanks really hard over the hill holding 1300deg at 60mph at the steepest parts. Weigh in at 26k gross combined. best improvment was the turbo, would like to add meth injection or a better intercooler next on day. The 4R100 just simply cannot control the torque of 7.3 pulling a load over a mountain at 65mph, even after john woods. better off adapting the allison (google it) or converting the the 6speed manual. you will see night and day difference. i wear ear plugs when towing in my 7.3 because after 3 hours my ears would be ringing.