Getting ready to swap a 5.7 into my 73 Dart Swinger

When you key the ignition on your throttle body will do a self test this is done every time the computer turns on. Remove the battery lead for a minute put it back on hold down on your gas pedal turn the key to on , not start. Then key to off then start. This will learn your throttle position. Make sure your maf sensor is hooked up.
The regulator you need is a corvette filter/regulator.