Hoping this is the right section. Not up on the gas stuff.
A friend just bought an ‘08 2500HD Silverado with the 6.0 gas engine.
It won’t start and history is that it ran fine till they swapped out the gauge cluster so they then tried a bunch of ecm’s and obviously it still wouldn’t start.

I’m assuming this is an L96 engine so what model ecm should it have and where can I find a stock cal file so I can full flash it and make everything happy again?