Resetting/Tuning Mechanical and Vacuum timing advances

Hopefully not.
Inside the vacuum diaphram where the vacuum hose connects to the distributor, there may be a small allen screw. Turning this inward slows the rate and vacuum level of vacuum ignition retard, and turning it outward increases the rate.
As far as the mechanical goes, you can remove the distributor breaker plate and see if the small black cushions on the ends of the reluctor tangs are worn off, or fallen off(common).
Personally, I hate running pig rich, and perhaps a quick dyno tune with an air/fuel reading would help. Additionally, the distributor could be set up on a SUN machine to taylor the rate of mechanical advance.
I usually will set the reluctor to the widest setting(14 or 16 most of the times), and then I know I'll get 28 or 32 degrees of mechanical advance. Then I can play with the vacuum on the car to fine tune.
I had a distributor one time that saw about 41 degrees of mechanical, so I just put a quick tack on the inside of the reluctor tangs, and then using a dremel, ground it every so slightly to get the correct mechanical advance.
Kinda hokey I know, put it's still working today.
(sorry so long winded)
Later.

Why not test to see if it's the timing that's actually at fault?

Simply retard the initial timing, which will also retard your total timing. If that stops the pinging, then start messing with your mechanical and vacum advance. If it doesn't help, then start looking elsewhere.

SadbutTrue said:

also, a guy i was talking to today implied that I would only have a vacuum advance, not a mechanical... is that true? I was always under the impression I had both.

What do the relucter tangs look like, I'll take a look at those this weekend.

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Like these:

Instaed of jacking with the timing, why not just pull off the vac line and plug it. Go run the car and see if it stops. That will tell you the story.

Ozsum2 said:

Instaed of jacking with the timing, why not just pull off the vac line and plug it. Go run the car and see if it stops. That will tell you the story.

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So simple, yet so effective

I disconnected my advance while waiting for the new dist. to come in. I opted for a new one, rather than rebuild the springs under the points plate.

If you had no problems for two years and then you started to get pinging, I am wondering if you have a vacuum leak somewhere that caused the leanness and you are masking it through jetting.

When something changes like that, I always look for the cause of the change rather than change something that you know couldn't have changed, like jets.