Help me get into the 12's for cheap

#1 Align the car and adjust the brakes. Align the car with the front raised 2-3" and the tires inflated on the high side of recommended pressure, as it would be under acceleration down the track. You want 3-4" degrees positive caster, .5 deg negative camber, and 1/8th inch toe in. If you have factory disc brakes on the front, make sure the calipers aren't seized. Check the seals and the pistons to make sure they move freely - any that don't can cause extra parasitic drag and slow you down. Check the rear drums and parking brake for free operation and lubricate as needed. Adjust the rear brakes to recommended specs then a little more on the loose side. You should be able to spin the axles by hand with very little effort.

#2 Shed some weight from the car. Unbolt anything not needed and remove it. Remove the crash bars from inside the doors, or swap to '70-'72 doors. Remove heavy insulated underpadding from the carpet, install newer and lighter insulation such as dynamat, reinstall carpet. Swap your heavy '73 front bumper to a '70-'72 version, or just buy a fiberglass bumper and lightweight brackets. Buy a fiberglass hood or remove some of the reinforcement underneath the stock one. If you have buckets, buy lightweight versions or swap to a bench. Remove spare and jack or at least swap to a small space-saver type from a late model car. Remove interior panels and go to town with a holesaw, reinstall panels. Swap to lighter wheels and a big/little drag set - 3.5" front runner is much lighter and causes much less rolling resistance. Many more but you get the idea.

#3 Engine upgrades. http://www.forabodiesonly.com/mopar/showthread.php?t=87402