Just to update/close this thread, I finally replaced my distributor - swapping the old, Pertronix-converted, one* with a full Pertronix unit - and the bouncing is better but still there. The car is running great with the new dizzy - I got it from Rocco/Mototron; it used to be on his race car and he thought it had a better advance curve for my engine - and I think I can live with the remaining bounciness. My inclination is to not worry about it and just leave well enough alone.
To prove some before and after comparison, I had a wonderful drive in perfect Alpine weather yesterday afternoon! The impact of the new distributor is subtle, but very nice. I really smooths things out. As for the tach, here is a video made in about the same area, at the same point in the drive.
https://youtube.com/shorts/zDqN1L0d_K0
For comparison, here is the old one that is most comparable:
https://youtube.com/shorts/KbDV757se1E?feature=share
Jim
*My old distributor was not the stock vacuum advance unit, but the mechanical advance one used in the H120 Rapiers. I switched to that one when I was running the DCOE's and never bothered switching back. The Pertronix unit is also mechanical advance.
To prove some before and after comparison, I had a wonderful drive in perfect Alpine weather yesterday afternoon! The impact of the new distributor is subtle, but very nice. I really smooths things out. As for the tach, here is a video made in about the same area, at the same point in the drive.
https://youtube.com/shorts/zDqN1L0d_K0
For comparison, here is the old one that is most comparable:
https://youtube.com/shorts/KbDV757se1E?feature=share
Jim
*My old distributor was not the stock vacuum advance unit, but the mechanical advance one used in the H120 Rapiers. I switched to that one when I was running the DCOE's and never bothered switching back. The Pertronix unit is also mechanical advance.