I have also found 12.7-12.8 runs best in my stroked hemi at WOT.

I have a 340 I will be switching over to EFI, maybe this year, so I want to get an A/F gauge on it now while its still carbed to see where it likes to be. Still trying to figure out my runs from last week where I thought it was a touch rich at Test & Tune on a mid 60* day and then went racing on Sunday at 85* day, and mph picked up and it spun the slicks out of the hole everytime and yet still went a 1/10th quicker. Its either the 10% ethanol fuel, or it was actually a little lean at Test & Tune. The fuel in the tank tuesday was pretty much left over from the previous year and I am pretty sure contained no ethanol.

Either way, I liked the results at the traps. Now I just need to find a way to get more traction.