I originally posted that only vac adv will change rotor phasing. RP is how close or far away the rotor tip is from the cap terminal when it fires. this is what you see/check with the timing light in the drilled hole in the dist cap. Crizila if your rotor is moving then you have the can hooked up. If you pull the hose and plug it then the rotor tip you see with the timing light will NOT move when you rev it, which is my position that only vac adv and not mech adv will alter RP. We got off on a tangent didn't we! I rarely get into these dogfights (I learned my lesson way back with the other double R) but I made a statement & they said I was mistaken so I had to defend my position! Krautrock, yes of course the rotor/reluctor/shaft all of it is moving but we are speaking of RP only (& what does and does not alter it) and vac adv will swing it thru an arc (a 11 deg can will effect a 11 deg arc that you will see in the hole in the dist cap and a good way to center that arc on the center of the cap terminal is the reluctor with the multiple roll pin holes (drill you own, I did)