Very cool car with the V8, console/buckets, and 8 3/4" rear. Definitely a unique combo for sure. You got real lucky with those floors and trunk too. I recommend a 15/16" master cylinder for reduced leg effort. Order one for a '73 340 Duster with power disc brakes. It will bolt right in to a manual brake car. 7/8" rear wheel cylinders help to balance the brake system too along with a proportioning valve.