I don't know specifics about the 6L80E, but something tells me nobody has addressed it in the aftermarket yet. Fab time.
An LS1 harness won't work with an LS3. Some of it may, but TBW alone is beyond LS1 territory.
'82 Berlinetta, 2000 LS1/4L60E. LS6 intake, shaved 317 heads, free-flowing air intake, long tube headers, 3600 stall, 3.73 posi. Best: 12.57 @ 109 at 5800' elevation; 11.82 @ 114 at HPT.
'57 Bel Air, my 1st car. In work: LQ4, L92 heads, LS3 intake, Erson cam; 4L80E, 4000 stall; 9".
'08 GXP grocery getter.
'95 Silverado 2500HD 6.5 TD. Just 335k miles so far.
'96 Vette Base Coupe. New to the herd.