diameter of distributor cam?

[timspider]

Need to know the diameter of my distributor cam on my 78.
not sure how to measure it. It's apparently either .715 inch or 1 inch.
Trying to install ignitor and need this prior to next step.
not in trusty manual.
thanks

[ScotcH]

You are talking about the cam inside the distributor that the points ride on, yes? I have not measured, but my 78 has a cam that is definitely not 1" ... smaller, so I assume it's 0.715". Do you not have a digital caliper? They are a very handy tool to have a round ... like $20 for a cheap one that will work just fine

[timspider]

Thank you. Yes, it's the smaller one. Will add a digital meter to my list of stuff at harbor freight.
And the igniter and new coil are now working! Now to get it dialed in.
Have a great day.