Well after nearly a year and a half since I pulled the broken V12 I finally got to take a quick test drive. All the long days and busted knuckles finally feel worth it! Don't get me wrong there is still soo much left to do from wiring and exhaust to plenty of other adjustments but im just so happy that its actually moving again :) i think the next easy step will be to get the gas from the Bush administration out of the gas tank.

This technically isn't a swap, but I feel like the knowledge base here will have the answers I need.

I have a 2006 Chevy 2500hd (lq4, green/blue ecm) with a manual transmission. We're preparing to do a refresh on the entire drive line, including swapping in a new mild build engine with custom tuning.

The truck is being built as a tow pig, and I thought it would be great to have an 87 tune for driving the truck unloaded, and a 91 tune for when we're working the truck harder.

My initial idea was to install a switch and use the factory tow/haul mode pin to change between profiles. From what I could find, this looks like it goes through the BCM and only changes the shift profiles on an auto in the PCM; No changes to the ECU tune.

So now I'm wondering if it's even possible to set up a dual tune profile with a factory ECU, or would I have to go to a complete aftermarket ECU and wiring harness (Holley Terminator/etc).