Join Date: Mar 2001
Location: Peoples Republic of Vermont
a. For a '66 289-2V without Thermactor emissions, factory timing spec was 6* BEFORE TDC, not after.
b. IIRC, curb idle for manual transmission, in neutral, is something like 625 rpm. If you can't adjust down to that figure, with timing set to spec, then look for binding of the throttle plates, sticking or maladjusted choke fast idle cam, or a vacuum leak.
Better yet, toss a vacuum gauge on a manifold vacuum source and tell us what the needle says...
FWIW, with the initial timing set to 6* BTDC, and with manifold vacuum for your vacuum advance, you'd be seeing the timing swing to around 28* BTDC.
What, me worry?
- Alfred E. Neuman