I just replaced my vacuum advance about 1 hour ago and what I did was pulled the #1` spark plug and as I turned the engine with the fan blades I felt for compresion on #1 cylinder and at the same time I looked for the timing ball in the flywheel window. When the piston came to the top I set the ball on the fly wheel to the timing indicator and took the bolt out of the vacuum advance, pulled the distributor cap off and marked the housing at the point the rotor button was pointing and pulled the distributor almost out and marked the dist. housing again at this oint and just pulled the dist. on out and switched the vac. advance and putt the dist. back in on the second set of marks and when it seated the rotor was pointing at the first mark so I was real close. I then took an ohm meter and set the points to where they were just breaking and tightened the vac.advance bolt back down and it started right up. I don't have my timing light with me but when I get back to Virginia I will put the light on it. Pilot