sounds like your gearing is spot on (for 1/4 mile) if your at the very top of 4th over the line
good times, any street car that runs sub 15 is fun to drive

for comparison i did 13.7 @ 99mph in my old ute which had 150hp at the wheels
from memory my 60ft times were always around 1.8-1.9
i had 4.3 diff gears but around 8500rpm to play with
i wanted to give it another run with the 4.88 gears that i used to run on the track
just never got round to it
id like to drag my white sedan one day, should be good for a mid 13 id say