Ok, I went with the vacuum method today and found best performance at 29 BTDC. That seems really early. The vacuum was highest, the needle smoothed out. I found that 33 BTDC at idle was best and some of the RPMs, but it seemed that it didn't make much difference down to 29. I think I saw 64 BTDC at high RPM with vacuum on.

I took it for a quick drive on some hills, and didn't hear any pinging.

Anyways, it seems to run pretty well.

Thanks for the suggestions!

Last edited by mshaw230; 07/15/18 02:20 AM.

Mark
'67 Camaro L6-250