You all have to remember to divide your vacuum in half and go 1 or 2 numbers less so 15 would take a 6.5 PV to start out with. Common factory engine Vacuum 15 and usual PV that comes in Street carbs is 6.5 as stated. Quick fuel or Proform's usually have a 4.5 to start
Also the face of the brass plunger is the seal of the PV on the body of the carb The vacuum source pulls on the opposite side of the spring not the threaded side. So if you change the length of the plunger you are defeating the seal. Make it to short it will be open all the time.
