is it possible? ive never seen it before

Changing your wheels to lightweight 15" weld rims also helps to reduce unsprung weight.

12's are possible NA with 3.73's, but you really have to start to reduce weight. I ran a 13.2 @ 104 mph NA with full interior, 15" welds wrapped in Nittos, and I still weighed in (with me in the car) at 3400 lbs.
 
Im pretty close and i have no suspension work. I think if i had some work done i could hit 12.99. Its a full bolt on car with 3.73's and ive ran 13.20 no weight reduction and it was on nittos. I think if i got rid of the seats got suspension and got full slicks i could do it.
 
This guy I know runs in the 12's consistantly. He's a damn good driver though too.
Here's his sig from another forum. I see him do it all the time. Oh, he's running on stock, cut springs to boot.

ENGINE:accufab plenum,75mm bbk TB,MAC coldair kit,MAC ultralite pulleys,Diablosport tuner

EXHAUST:flowtech longtube headers,flowtech x-pipe,flowmasters 2 chambers

DRIVETRAIN:lakewood machine bars,tremec t-45,b&m rippershifter,centerforce clutch,3:73 gears


VISUAL:relocated spoiler,smoked headlights,mach1 grille delete,springs,bullitt wheels,mach1 shift knob

slicks best=12.80at 105.9mph 1.7 60ft
streets best=13.33 at 105mph 2.0 60ft