I checked a friends timing the other day on his 12.5/1 396. I plugged the vac advance, the initial was at 10 and the total was at 30. Seemed way low. So I advanced it to 16 initial and checked the total and it was still only 30...? What's the deal? thanks. BTW he had a terrible bog when trying to accelerate which improved advancing the timing but didn't completely go away.

Faulty vacumm advance? One day my dist just lost it--it just stopped working.

I would say that something inside the dist is holding the mechanical from advancing.If you had 20* mechanical before it should still have 20* no matter where you set the intial.When you reset the intial did you back the idle down to where it was if you didn't you could be into the mechanical advance already.

Maybe the weights are sticking on the mechanical advance...