The 6.0 had a lower incidence of repair under factory warranty than the 7.3. The 5R110 is a better transmission than the 4R100, which is just an outgrowth of the E4OD, which wasn't exactly praised for its durability. The 5R110 is good to about 600RWHP. I run a Ford reman trans behind my 6.0 pushing about 505 to the rear wheels and 660 at the crank. 120k, zero problems. The original trans went out at 68k, but that was almost certainly the fault of the Edge tuning I was running at the time. You can build the E4OD/4R100 for power, but the 5R110 is just a better starting point. Eric at Innovative Diesel has one in his truck that runs 10.40s. Aftermarket clutches, no billet shafts, no valvebody trickery. So yeah, its plenty stout.
Look into the Cummins swap and you'll see why so few people do it. For one its really expensive because those engines still command $2,500 or more even with 300k on them. The trans is a huge issue because no stand alone controller really works for a 5R110, so you have to either use an Allison or a Dodge trans (talk about junk). The electronics of the swap are a nightmare because you are going from a computer controlled engine to one that isn't. You'll have well over $12,000 in that swap by the time you are done and you'll have a bastardized truck that uses a lot of specialized parts that are not obtained quickly should any of them fail. The power of a stock Cummins is a joke compared to a 6.0. You have to modify them a fair bit just to get on par with stock 6.0 power levels, let alone what you can do with some tuning. The best Cummins is the P-pump version which commands the highest premium and is hardest to find, and even then the top dog was rated at 215HP, so 110 less than the 6.0. Sure, you can do the fuel plate, injectors, etc., but then that adds even more to the cost.
I imagine that swapping in a 7.3 wasn't that tricky, probably mostly bolt in because the truck really didn't change much in '03. The big question is simply why? It seems that he ran from an engine he didn't understand to one that he did. The 7.3 was a good engine in its day, but its day has passed. Its demise was a combination of not being able to configure it for emissions and not being able to get enough power from it to stay competitive with GM and Dodge as the Diesel HP war started. If you take care of it and address the weak links the 6.0 is a 500k engine that can make some serious power. I drive mine every day and the truck gets worked. Over 190k, owned it since new. Not a single repair to it that wasn't my fault through my quest for power or out of ignorance. That's reliable any way you slice it.
'06 F250 4x4 - 5" Flo Pro exhaust, SB Filter intake, Accufab elbow, Edge Evolution (monitoring only), SCT w/ ID custom tune, FASS 195 pump, Gillette Diesel EGR cooler delete, Sinister Diesel coolant filter, ELC coolant, updated turbo drain tube/oil feed line/STC fitting/oil cooler, ARPs w/OEM HGs, Elite coolant lines, ITP RR fuel system, RCD 175/30 injectors, Powermax, BD CCV, FICM.com FICM w/ ID tune, Elite UP, BPD water pump - 13.069 @ 101.94
'02 WRX - Outback rear disc swap, EBC green pads, DBA pillar vane rotors, TXS UP/TBE/TMIC, Perrin LW crank pulley, PPG billet steel shift forks, ACT Streetlite flywheel & clutch, K&N filter, STi Group N motor/trans mounts, TiC/Kartboy rear diff mounts/subframe lock bolts/outrigger stiffeners, Kartboy SS & all shifter bushings, custom PDX tune for Cobb AP - went 14.1 on a terrible 60ft before most of these mods; shooting for 13.50s
Last edited by TKOPerformance; 12-13-2016 at 09:14 PM.