blacknwhite71
There are some strong opinions here on dial back lights versus standard lights. I've got a Mac dial back from the pre-digital era that I bought used when I was working as a mechanic 10 years ago. I used it on lots of cars without a problem back in the day, but can't remember a 6AL and my Chevelles don't have 'em. There are others here that know more than I.
There is a different way to decide what to buy. The dial back lights cost more, but you don't need one if a.) you're not interested in what your total timing is because your set up is stock or close to it; or b.) you use timing tape on your balancer with a standard light. If this is a new tool for you and cost is a factor (as it often is) maybe it's best to start with a standard light.
To your question about how to set timing. Re-read the post from greg_moreira. The timing light will have jumpers that go to the battery that powers it, and a cable that clamps around the #1 spark plug wire. The timing light gives a strobe effect that you aim at the balancer and timing tab. There is a line on the balancer. The strobe effect "freezes" the line on the balancer against the timing tab -- you read the line of the balancer against the marks on the tab, which is in degrees. Unhook the vacuum advance to the distributor before you do this. To change the timing, you loosen the distributor clamp and move the distributor (but move it a VERY little bit). As you do this, you can watch the line on the balancer "move" in relation to the timing tab. The dial back light works on the same strobe concept, but instead of reading the degrees off the timing tab, you "dial" the light to the correct degrees and then read the balancer line against the zero mark on the timing tab. Post back if you need more detail. Good luck!
