I think you're doing ok. I bracket raced a w-2 360 Challenger @ 2,800 lbs and had high 1.37 - 1.40 60's running 10.20's @ 129 - 131.

If footbraking, fine tuning the squirters and pump cams may help. Tuning for a trans brake would be a bit different which I'm not familiar with.

Stock and Super Stock cars usually have even better 60's for the ET for various reasons, mainly through a lot of work with everything. (Experimenting with cams, converters, gears, shocks, etc.) I've had high 1.40 60' times with 11.20's @ 115-117 weighing 3,540 lbs +, but there are harder leaving cars in Stock with similar ET's & MPH.