Copy that. Thanks. I have never seen this kind of jumping around ever in my life. A degree or three maybe, but no more than thatThat sounds more like a timing light problem. If your timing was really jumping around that much it probably wouldn't run.
First, assuming you have a clamp on type light, try moving the clamp to a different location on the wire. If that doesn't help, try a different light.
Thank again for all the advice! It is very much appreciated and I will replace the timing chain this year.When the cars were newer, about 80K miles and the "borrowed time" syndrome started to happen, by observation, especially on some GM engines. At this point in time, on your car, it's more about "time" than "miles".
Now that you've got things going pretty well, get a name brand (i.e., Cloyes) timing set and put at least a new chain and cam sproket in it soon. Going to a roller chain will be a "once-in-a-lifetime" deal as they'll last that long with no issues, from my experiences. A roller chain is CHEAP long-term insurance in basic engine longevity. Douse the new timing chain parts in oil before putting the front cover back on, for good measure.
In using an inductive timing light pickup, find the place on #1 wire where it's the most isolated from the other wires, for best results. As an alternative, you can also use #6 as it's the first cyl in the 2nd half of the firing order.