Stockity stock stock big blocks from say the late 60's like to sit around 10-12BTDC at idle
(hose removed and plugged at carb, of course) - but that doesn't matter nearly as much
as your "all-in" advanced timing.
If you have anything near a stock distributor on the thing, get some timing tape on the
harmonic balancer (or just do what I did, marking the balancer at 10 degree intervals by
measurement and a Sharpie).
If your centrifugal advance is working decently in the distributor, buzz that rascal up to
around 2500RPM and check your "all in" total advance there.
Most of these stock animals like anywhere from 32-36 degrees total advanced timing; play
with it some and see where it's happiest (smoothest) at that RPM.
The engine will tell you...(and you can always play along at home by hooking up a vacuum
gauge for verification, as best vacuum is typically most smooth).
Then whatever the timing is from there when you let it back down to idle is what it is....
provided the advance works, it'll probably be somewhere in the mid-teens BTDC.
Set it and forget it.
[/QUO thanks for the help