I checked the archives, and Steve Brotherton's posts on vacuum advance and timing, and I think mine may be out of specification:

Timing is set to 4 degrees ATDC at 800RPM with the vacuum advance hose in place. When I remove and cap the vacuum hose, the timing changes to 23 degrees BTDC at idle, and 45 degrees BTDC @3000 RPM. Idle speed increases considerably with the hose removed.

Is this OK or should I investigate further?

Thanks,

Steve
1969 280SL