Different car but shows what improvement you could expect if you follow the same procedure.
When 15 my friend and I were giving a 120Y by his grandmother.
He lived on a farm with a long dirt driveway. We marked out 400m and laid a blistering hand timed 21 secs.
We then got his Dad's tools out and removed: Bonnet, Doors, Bootlid, Windows, Seats (all of them), Contents of the boot, All Carpets and underlay, Lights, Bumpers, Front guards, Inner guards and then stood back and had a look. At this moment we thought we could do better so got the angle grinders out.
Cut off the roof and as much of everything else as we could.
In the end it had only the motor, gearbox, dash and suspensions mounts intact otherwise it was as flat as we could get it. Fuel filler was held up,to stop leaking, with a piece of fencing wire and we used a plastic school chair(also held in place with wire) for a driver's seat.
We then timed it again and got a best of 17 seconds flat.
So, if you do the same thing to a V6 Commodore, you should get into the 12second bracket given we obtained a 4 second decrease in times using only the stock motor. Given the extra torque you may get into the 11s.
Give it go and let us know how it went or just supercharge it.