<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Kurt S</div><div class="ubbcode-body">38 deg total at what rpm?
You want that vacuum advance hooked up - remove the plug. And make sure it's connected to manifold vacuum, not ported vacuum.
http://www.camaros.org/pdf/timing101.pdf </div></div>
All in by 3200 RPM. That is a good write up and makes allot of sense. A Z28 has 3.73 to 4.11 gears and turns allot of rpms when cruising. I know your vacuum drops out under acceleration but when you are cruising at 2800 RPM with a load on it wouldn't the vacuum come up and add more timing causing detonation that you may not hear. With 11.1 compression and todays fuel I would be worried about that.