Any 12 second combos with 3.23s?

Hey everyone,

Anybody have any 12 second cars while using 3.23 rear end gears? I know its not desired but i put the majority of my miles on the freeway (just drove 900 miles to Mopar Nats). With that im still hoping to crack into the 12 second area with these gears.

Current setup
71' 340 Duster
4-speed with 3.23s
Mild build, Lunati 60403 cam, 273 rockers, LD340 intake with Thermoquad, Hooker heads to 2.5" x pipe exhaust to the rear bumper.
Radial street tires
Current best time is high 13s @ 103 mph on a failing fuel pump.
60' time was aweful so thats more drivers error.

I know im fighting physics but i would like to see if anyone has a comparable setup.