i just went out to set my timing because my cars been running rough, and i forgot to disconnect and plug my vacuum advance line. when i realized this i was surprised because i was at 7 deg btdc and from what i understand, with the vacuum connected it should have been alot higher. i then pulled the line, nothing changed, i pluged the line with the tip of my finger and i was still at 7 deg. also there was no feeling of vacumm going through the line whatsoever. whats wrong? is all i need to replace the vacuum cannistor or is there something else? i'm runnning a 327 cu SBC, HEI with accel super coil and new plugs (AC Delco rapid fire) and wires (Auto lite 8.5 mm stock replacement)
Thanks for your help,
Brendan

If your vacuum line is attached to "ported" vacuum, you'll get exactly that result. It doesn't allow the dist. any vacuum until the throttle blades are open. Try plugging it into manifold vacuum to see if the advance is ok.

Dave