08 Sierra Vortec Max engine swap

dirtdriver11 · February 16, 2020

I got an 08 Sierra Vortec Max with around 245,000 miles on it. Debating whether to rebuild, reman, or new crate. My truck has the L76 engine, if I swapped it out for a L96 what all else would I have to change? Computer or wiring harnesses? Mine already has the afm/dod delete done on it. Any other suggestions?

CamGTP · February 16, 2020

It would swap in. If your current truck has the VVT delete as well you would likely want to re-enable that in the computer because the stock L96 6.0 uses the VVT to make it's power.

The L96 has lower compression than the L76 if I remember right too.

I guess one of my questions is, how is the AFM/DoD currently deleted on your truck now. Is it just a tuner than shut it off, the range dongle OBD2 plug in or did you remove the parts completely and swapped them with non AFM/DoD camshaft/lifters/trays etc etc.

That will determine what other tuning is required on this engine swap.

dirtdriver11 · February 17, 2020

The work was all done before I bought the truck but here is a copy of the receipt that came with truck.

CamGTP · February 17, 2020

A couple pieces of that puzzle seem to be missing.

The DoD valley plate and the lifters were replaced but it didn't mention anything about swapping the camshaft or lifter trays that also have to be done. No parts listed for head gaskets, timing cover gasket and so on. It also only lists 2 pushrods, were as 8 would be needed to replace the 8 that were removed for the DoD lifters. Just seems odd is all.

The big picture is that a L96 will swap in. Past that I would still want the tune looked at to make sure the VVT camshaft is allowed to function. I just don't know what they did with the calibration with the current engine in it.

dirtdriver11 · February 18, 2020

Not for sure on all of it. I just know that it never switches out of v8 mode.

swathdiver · February 18, 2020

He would need to have it tuned again as the L96 is a FlexFuel motor with much larger injectors. Both use the same computer until 2011 too.

dirtdriver11 · February 24, 2020

So the L96 will bolt up to my 4L70E transmission? Anyone no for sure if it would have to be tuned or not? I have heard it both ways now.

CamGTP · February 24, 2020

Yes, it will.

You have to swap your flex plate over because the L96 only came with a 6L90e transmission.

The tune part is already something you should look into. We have no way of knowing exactly what was changed before.

So if you swap the long block over, then install your current intake manifold, injectors, throttle body etc etc. From there I would just see if it starts and runs like nothing happened.