These are some tips and tricks that I've used with good results.  Not all of these are specific to the AMC 6, but they are specific to bracket racing.

Driveshaft Loop:

I use a Lakewood driveshaft loop.  I cut about 5” from each end of the loop arms and used those pieces as spacers between the loop arms and the car floor.  New holes were drilled to match those in the spacer pieces, and it was bolted to the floor.  Even if you don’t run slicks, this is only a $20 mod, and it could save your life some day.
 

Traction Aids:

I use the cheapie Lakewood slapper traction bars with good success.  The improvement in 60 foot times and consistency these made to the car even when it was running in the 17’s is well worth the $30 investment.  I don’t believe extreme duty traction aids like ladder bars or a 4-link are necessary at this performance level.  If you want to splurge for a better traction bar feel free, but none will weigh as little as the inexpensive Lakewood bars.  Whatever you do, make sure the rubber bumper ends up as close to the front spring eye as possible.   I'm running about 2 ½" of gap between the rubber bumpers and the leaf spring in order to apply a shock load to the tires to force them into the ground.
 

Battery Relocation:

Relocating the battery to the passenger side of the trunk will help traction and weight transfer.  NHRA requires a steel hold down bracket, 3/8” hold down bolts, a master disconnect on the positive cable, and a firewall between the trunk and passenger compartment.  Check the current rulebook for firewall thickness requirements.  This is also a good time to relocate the starter relay to the lower passenger corner of the engine bay (near the brake differential pressure sender) to minimize cable runs.  Use 2 gauge cable for the main run along the frame rail to minimize voltage drop; all else can be 4 gauge.  Cable ends should be crimped on and then soldered with a propane torch.  Finish the ends with heat shrink tubing to minimize exposed positive cable.
 

Sway Bars:

Remove your front sway bar if the car was equipped with one.  This will reduce the weight on the front of the car, promoting better weight transfer to the rear tires.  A rear sway bar should have little effect on your quarter mile times at this performance level.  I would remove it (if so equipped) just to save weight.
 

General Weight Removal:

The light weight of the AMC body design is definitely an advantage, but it can be improved upon.  Here's a few items that can be removed/modified to reduce your weight and increase quarter mile times.
 Change from power to manual steering
 Remove air conditioning system
 Replace cast iron intake with aluminum
 Replace cast iron exhaust manifold with aluminum
 Rear seat
 Passenger seat
 Horns
 Heating/defroster system
 Undercoating
 Use fiberglass body parts

Weather Stations:

You will not go very far in Bracket Racing without the ability to predict the changes in your car's performance due to the weather.  My dial in changes every round, and if it didn't, I wouldn't have a chance.  I use an inexpensive set of temperature, humidity, and barometric pressure gauges in addition to a program I wrote for my calculator.  Many companies have similar setups available.  An inexpensive alternative is the Barry Grant Weather Factor Slide Rule.