I thought I would create this thread because I don't see a lot of posts about what kind of horsepower these trucks are capable of making. Over the weekend I attended Schied Diesel Extravangza. Curious as to what kind of horsepower I was making I decided to dyno my truck. My truck currently has a H&S Black Maxx with the 300 HP tune, a 4 inch Flo Pro with stock down pipe and a S&B cold air intake. I ended up dynoing on 2 dyno's back to back. The first dyno was Schied's mustang dyno. The truck ended up making 475 HP and 1261 ftlb tq. I let the truck cool down for about an hour and changed nothing. Then I put the truck on DP Tuners dyno. There, it made 597.8 HP and 1116 ftlb tq. I have no clue why I got results that were so different. Schied said it was because of the differences in the dyno's. Some of the other 6.4's had similar Results that I saw dyno. Mine however was one of the higher ones. Anyway, I just thought I would give everyone a heads up as to what these trucks are capable of and see if anyone had similar results.
Scheids I believe had Beans dyno and that dyno reads notoriously low. My truck running the Spartan 300 tune laid down 560 and 1170. 6.4s with big tunes will generally be in the 540-570 range with tuner, exhuast and intake. Reason they have to be done differently than gas is you have to load the dyno so the turbos will light to their full potential. If you aren't loading the truck, your numbers aren't going to be accurate.