Headers & Cam upgrade or Rear Gears

3.91’s. Then do wider tires. Something like 245/60/14 should be available. Tire diameter will change the speedometer reading. A new gear in the trans should help a lot.
How much of a difference do you think the 3:73’s would make ? And do you have any information on the new gear in the trans you mentioned ?Any idea what that would cost me at a reputable transmission shop ? Sorry for all the questions not to familiar with the internal parts of a transmission.