Congrats on the E-85 swap, nothing like high octane for less than 87 octane cost. Do you check the content of ethanol in the fuel you pump? Not sure if your in a climate where winter blend/E-70 is used. If you have a A/F gauge it will show richer than your target A/F you'd see with E-85(E-85/11.6 E-70/10.6 est.).
We have had issue with it here in S.Fl, I thought I'd post about it in case you were not aware. Goodluck at the track, Andy