Several years ago I was going to build a 71-72 TQ 340 based 904 backed Duster for F.A.S.T. but about that time they asked me to be their Tech guy so I got side-tracked and sold the car. It was a 72 Twister /6 car in really nice shape I sold to B body Bob. I was planning a 4.1 x 4.1" 433 motor using light 2.05" thin stem intake valves and my own cam specs.

Take full advantage of the Duster's long rear overhang, just 10 more static pounds added behind the bumper (like adding the 13 pound 1973 reinforcing plate) can have the same dynamic effect as putting a 40 pound battery 1 foot behind the rear axle centerline. Duster's and Chevy II wagons are the best "natural hook" cars I've ever played with.

Have the allignment shop physically jack the front end of the car approx 1-1/2" inches BEFORE setting the allignment....this will simulate the car under acceleration and decreases the rolling resistance down the track. Dynamat in floor of the spare tire well adds a few strategic pounds in just the right place as well.

Amsoil gear lube is typically worth at least ~.03 on most cars I've ever back to back tested...I like to get some heat in the rear axle by idling the drivetrain on stands in the pits for a few minutes.

If you're serious about it dyno-tune the car on a chassis dyno before the race documenting every 'cause and effect' jetting and timing change.