4L80E Standalone computer question.
Youc an mod your stock harness by re-pinning it at the trans from the 4L60E to the 4L80E and adding the 2 wires for the front speed sensor, then have someone at HPTuners change your OS to work with the 80, and tune it with HP Tuners.
That's what I am doing on the cars I do LSx conversions on.





