Timing Dance ! Vacume Advance ?

dgc333,
Yes it can be a benifit and make a motor run cleaner.
You sould run the vacume advance if you have a stock distributor.

If you run the vacume advance on a modified distributor, you have to be really careful with what you dial the distributor in for and how much timing you give it.
If you don't have a big enough cam in your car and have a motor that has very high cylinder presure your taking a chance with detination.
For example:
Your driving your car down a road, and you have to climb a hill under part throttle.
You gave your car 35 degrees total mechanical advance and you have 15 degrees extra the vacume canister is giving you.
At this point you are at 50 total degrees timing and are having detination problems.
So you dial the vacume advance back to 5 additional deegres.
Now you have 40 going up the same hill due to the load on the engine.
A engine that has high cylinder presure will still most likely have detination problems.(smaller cams \\ no gear \\low stall convertor)
When you run a bigger cam ,AND HAVE LOWER CYILINDER PRESURE you can run the vacume canister BUT BE CAREFULL.

I don't take the chance of being in the wrong situation and having the motor pay the price.
FOR EXAMPLE: HOT DAY\\BIG HILL \\ THREE QUARTERS THROTTLE.
REMEMBER (((( YOU CAN'T ALWAYS HERE DETINATION))))

If it's all about drag racing then it gives you no benifit, and you will not have any detination problems creep up on you.

It can help your fuel millage for sure but you better now what your doing and what your motor is doing under all kinds of driving.
Detination will kill a motor faster then carbon.
I don't have to worry about carbon because i run alot of gear in my cars and they don't carbon up that easy.(higher rpm's)

If it works \\ keep doing what your doing \\ It's all good.
The factory put vacume advance on the distributors for a reason.
It's all about drag racing for me and some times being in the middle isn't so bad,JUST BE CAREFULL.