The typical LPO number is LM7, they came in 99 and up Silverados, vans, and SUVs, they are pretty much the same until 08. If it has the older 411 PCM thats what you want, its the PCm that runs Vettes, F-bodies, and trucks, super common, cheap and flexible. That is what I'd look for, these engines will have teh cam sensor on the top back of the block behind the intake, knock sensors under the intake, and a 24 tooth reluctor ring on the crank. This is what I'd look for.