Where to set timing

The best way I ever learned to set timing is starting from the stock timing:

*advance the timing and keep adjusting the idle down until the motor quits idling faster. That is what your engine wants as initial. Measure that with a timing light.

*Know the total advance known to work with your combo. I use 36 degrees total for big and small blocks and 32 degrees for Slant 6's. Your combo may need less total if you have high compression and/or a variety of other factors to avoid gas knock or detonation. Subtract the two. That is your mechanical advance added by the distributor. The rate at which it comes in is governed by the springs and weights.

*modify your distributor's advance (usually by) limiting = welding up or filing the advance slots a bit. I use a mig welder and a chainsaw sharpening file. This is trial and error, and you may have to put the distributor in to measure total timing. Remove and repeat until you get the exact amount of added timing to reach the given total advance.

*you now have to adjust the rate and rpm at which the distributor adds timing, by adjusting the strength of the springs. Change to lighter or heavier spring rates.

* adjust your vacuum advance. Mopar offered several different amounts the cans can add, most are internally adjustable with a very small allen wrench through the vacuum nipple. There is also a stamped in step which limits the amount it can add.

* If you set your motor up this way, you must hook the vacuum to manifold vacuum, NOT ported vacuum. This allows the vacuum advance to drop down as the throttle opens reducing the advent of gas knock under load.

It is a time consuming, but very effective way to enhance drivability, gas mileage and performance. I have done this on many friends cars with great success. They have all reported that it is like driving a different car once it's done. Unfortunately, one friend was so used to driving his Eddy headed sixpack motor with such low performance, that once I tuned his timing, the motor made so much more power that it broke the tires loose in 2nd gear and he wrecked the car. He panicked and just left his foot in it. So be warned.

My slant 6 liked 24 initial and 32 total. It would burn the tires off from a start with 2.94(or something like that) rear end gears after I tuned it.