Not saying the calculators are wrong but every car i've seen running 5.30's is in the low 1.20's 60' times and i don't know if you can do that with a footbrake car, you have too remember that the first 100' is the biggest gain in ET, the rest is smoking a cigarette and eating a sandwich. Put a transbrake in it and i'm sure you'll see the big improvment you are looking for.
JMO
Zip.