Thanks, I ordered the Inline-6 Adapter etc. but as Rawze said, it was a programming issue, I switch the ECM on my brother's truck and it did the same thing. I put his own on my truck and it rev properly, everything was ok.
Thanks for all the help guys.
sounds like a bad delete. like other have said, drop those cans and make sure they are all (DOC, DPF and, if applicable, SCR) 100% empty inside. It's not enough to have some hole drilled in there and if any of the cans are not hollowed out then you will end up with problems. and of course that programming needs to be fixed, by someone who actually knows what they are doing!