Alright I'm sure this could be in a couple different sections so bare with me, hopefully I'm not to far off in general help.

So I inherited this problem, my uncle passed in January and all this work was done by him. Also I'm not 100% I know or have the correct info going off what he told me.

07 late model Chevy 1500 was originally a 4.8 ly5 truck.

My uncle acquired a gen 3 l33 engine for cheap. He had been tracking a misfire in the 4.8 for years and was done dealing with it.

He took the l33 to get rebuilt, in the process find out that the two engines were different generations. But somehow was told all he had to do to get the gen 3 to work off the factory pcm was to have the tone wheel pressed off the old crank and pressed onto the l33 crank. Engine builder didn't have the correct tool to do this so he bought one and supposedly the engine builder swapped it. Once the engine was rebuilt he reinstalled it. He did drill out and tap the lower bungs to install the knock sensors in the engine block vs in the intake.

Everything is in. When I had a scanner I scanned it and watched that I had engine speed signal. But the engine never even tried to fire. I'm trying to get this truck running for his kids to keep so I'm trying to find out my options.

Did he royally screw up and I have to pull this engine back apart? Or is there somewhere to start with to check and get this engine to run? I'm unsure if this is correctable in tuning or if I need to inspect and change parts to get everything to work together.

I'm sure I'm missing something or getting some information mixed up but this is what I was told. I pulled the engine for him and then came home a few weeks later with him putting it in. Wasnt involved with any of the rebuild stuff or part swapping. Just trying to get a starting point.