Swapping a 6L 4L80e into my 05, I got the o2 sensors off the 6L donor truck cause I knew the plugs were different than my 4.8. Question Is, do I need to use the 6L sensors or can I just keep the 4.8 ones? I was planning on keeping the original harness in the truck but I do have the donor harness aswell. Will also be running a 6L pcm. I do have hp tuners aswell. Thanks guys

 

Just swap the long block, use everything from the truck gonna tune it anyway. That’s what I did and did the repin for the trans and segment swap.

 

The 4.8 o2's will work with the 6.0 swap.
I went from a 4.3 to 6.0 and used the original 4.3 o2's

 

O2s don't care about the engine size. As long as the connector hooks up you're good to go. In this case, leave the 4.8 ones in there; if you were swapping harnesses too, you'd use the 6.0 ones.