The number 1 and 2 quickest bolt-on 5.0s (stock long block no power adder) in the country (wbt and caspergt) (both autos btw!) run the 1/8th at around 6.95 and 99mph (10.78 and 10.87 in the qtr) with only around 450hp-460hp and weighing around 3500-3600 lbs with driver so you should be able to beat that with the HP you put out (I'm assuming well over 600 with what you have.)
Here's wbt's thread:
CLICK HERE
Here's caspergt's thread:
CLICK HERE
I would say you should be able to do low 10's or even a 9.90 in the qtr as Daniel Pachar down at TSS in Orange TX has a couple supercharged GT cars (non-Boss) with your type of mods running those numbers.