Sorry Capt..
Take a Duramax with a simple tune and it will roast a EcoDiesel. I've owned three... my dad owns 2 currently.
Now, saying an Allison is junk is really laughable. We all know once you tune a Duramax with twice the stock power. That's when they have problems..
The Allison is a...
A GM 6.5 Diesel shouldn't even be in this conversation. Not to break any hearts around here, but a EcoDiesel isn't going to keep up with a properly tuned Duramax (or newer Cummins). Two different animals.
You may post to other forums. It's sad that forum doesn't allow other forums to be posted. I'm here to help you guys, and all the info we can gather is always best for us!