I a little confuse about something. From what I heard the total amount of timing you should have is between 30* and 38* @ 3000RPM depending on your preferance. I have a total of 56*. I have an initial timeing of 12* with the vacuum unpluged @ 3000RPM its 34*. With the vacuum connected its around 56* @ 3000RPM. I contacted Accel and they told me the distributor wouldn't go that high. I was thinking I had a problem until I saw this post. His settings are very similar to mine.

http://www.chevelles.com/cgi-bin/forum/ultimatebb.cgi?ubb=get_topic;f=5;t=003244

So what's up?????

Sounds like you have approx. 20 * mechanical (this is good)

Your vaccum advance can be adjusted if you have the Accel HEI..sounds like you have 20* in there too.Cut it down so its about 5-10* vacuum advance.

Your base/mechanical sound OK basically

"total" timing DOES NOT include vacuum advance. You're very likely just where you want to be. As long as you have no part throttle ping, the vacuum advance should be OK. Feel free to play with it some, bring in a touch more or less advance, perhaps at a lower RPM. There may yet be some small gains to be made, but you're already very close.

When you say "total timing", it means your base timing plus your mechanical advance. In your case, you would have 34* total timing in by 3000 RPM.

Vacuum advance only happens during part throttle and isn't present at WOT.

EDIT: Schurkey beat me to it

Vacuum advance comes and goes with engine vacuum. Using the numbers you provided you have 22degs of vacuum advance.

Thanks guys. I had my defeniton of "total timeing wrong".

You are seeing vacuum advance at 3000 rpm because you are reving the motor without a load. It's not undergoing the same conditions it would see if you were truly accelerating the car at full throttle, in which instance 56deg of advance would shortly kill your pistons.

At full throttle there is zero or very little vacuum 'seen' by the distributer. Therefor what you are to be concerned with is setting your initial and mechanical advance to it's optimum.

Adjust your vacuum advance so that you do not get any pinging while you are driving around at part throttle. As much as it will tolerate.