wrote:
Bigger bore cylinders (like an IO-360) should show even more mag drop
than small cylinders (like an O-300). It takes slightly more time for
the flame front to get across the cylinder head. Something is wrong
here.

Thanks everyone. Despite gorgeous weather here, I haven't had a chance to try it
again lately.

Partly based on the feedback from this group, I went back to my partner who
manages the maintenance and asked him to investigate it a little more. He says
he tried it and got a 25 RMP drop on each mag. I haven't been able to check it
out again myself, but I'm wondering why he sees a 25 RPM drop and I saw nothing.
Anyway, that's where it stands for now. I'll let y'all know if I learn anything
more. Thanks for all the information and advice.

Dave