5.3 and a turbo will loaf to 11.40's in a C10 short wheel base.
I've been 11.44@118.69 on a 1.62 60' with a 3.25 gear, 10 psi at 4100lbs.
The C20 makes it tougher due to weight, but don't doubt the miracles a turbo can work for acceleration.
Here's a video last year of my 2nd trip to the track.
http://youtu.be/8DCkwtT71E0