Setting dwell angel and setting point gap accomplish the same thing. On my 64-1/2 Mustang I have to remove the distributor cap and loosen the set screw on the points. Place a screw driver in the slot for adjusting and twist until the gap between the points is correct. The cam on your distributor shaft must be aligned with the nub on the points. This achieves the Maximum Gap your points can achieve. It also determines your maximum Dwell angle (Angle is nub- points pivot - points tip). Tighten set screw when gap is correct and check for accuracy. Withthe car running and a dwell meter connected you can confirm proper dwell angle. Some cars have an adjusting screw external to the distributor cap so you can adjust using a dwell meter while the car is running.