All you experts out thier!!!! I need some assistance with a choice of running a 3 speed AA tranny or run a 2 speed glide.???

I plan on running a 727 Allison trans w/ brake in my Scamp that is built with the best parts money can buy.5000 stall convertor. running 500+ inch motor and 4:56 gear in my Plymouth Scamp, car weighs 2500 pounds.
Now I have a chance to get my hands on a Glide w/ tranny w brake. My hang up is that a 2 speed is a slow dog out of the hole?? Will this hurt the ET.
Any advice from those that switched..