Will I notice relocating my battery in my 60'

The launch doesn't appear "bad", but maybe the 4.10 gears hurt 60' more than I think. I don't know what works best with a trans brake, but with a lot of time and patience, it's possible to get a double pumper to work fairly well footbraking if it's sized correctly. You don't have the gear to accellerate better so you have to look for torque within the combo. Stroker motors and big blocks can get away with less gear because they make more torque through cubic inches.

A low gear set for the 727 would help off the line and not hurt highway fuel mileage. But they are expensive, plus installation. Then if it launches harder with a trans brake, you may have some durability problems with the 8 3/4" ring & pinion and/or differential caps. Some people have had good luck with a brake or 4-speed in front of an 8 3/4 while more have not. I wouldn't be comfortable with it.