05 engine in 07 classic (gmt800)?

SpinelessCord14 Smith · November 1

Hello, I am about to purchase a cammed 5.3 iron block out of an 05 Sierra. I plan on installing it in my 07 classic (same thing as the 06) it comes with the PCM thats already tuned for the cam installed in that motor and has a drive by wire throttle body just like the one that’s in the 07 now. Basically my question is will there be any problems with vin matching or anything of that sort? Or what’s the most common issues?

CamGTP · November 1

The engine will work but the computer I believe will not work.

The PCM, throttle body, pedal assembly and TAC module all need to be matching for it to work. There are part number differences from 2003-2005 and 2006-2007 trucks.

The best to go about this would be to pull the tune off the 2005 computer and copy that data into the 2007 calibration. It would take someone with HP Tuners or EFi Live to do this. And not all tables can be copied over because certain throttle body related tables are not the same between years and will cause reduced engine power errors to come up.

After the data is copied over, you'd need to fine tune it the rest of the way and then see if you need any other parts to make it safe. It's possible that your 2007 truck won't have big enough injectors or that is has different injectors than what the tune on the 2005 truck had. So that is another things that needs to be addressed.

It's usually never as easy and plug in and go when using different year computers with unknown information about the full parts list used on that engine.

SpinelessCord14 Smith · November 2

@CamGTP the 05 engine is a complete long block, it comes with intake manifold fuel rails, injectors, accessory drive, etc. I believe it has an oem drive by wire throttle body (the same that is in the 07). Also forgot to mention I would be using the factory wiring harness that is in my 07 bc the motor I’m buying does not come with it, could that cause some issues? Thanks for the reply since this is my first engine swap.

SpinelessCord14 Smith · November 2

@CamGTP if I reuse the throttle body on my original motor if they are the same would I still have the compatibility issue?

CamGTP · November 2

Yes, you'd still have issues because it's not just the throttle body that matters. The PCM and the throttle body, TAC module and pedal assembly need to be matching.

I'd have to go down the rabbit hole of tracking part numbers but from what I recall the TAC module and throttle pedal have different part numbers from 2005 and 2007 and the calibrations are not the same between those 2 years.

Your wiring harness on the 2007 will work just fine for the swap, all of that should plug into the engine just fine. Just the 2005 computer is the hold up. Like I said with copying the tune and making it work in the 2007 computer is one solution or having someone custom tune your truck with the new mods is the other option.