360 timing issues

At idle, with correct valve timing events, your engine should be happier the more timing you give, up to about 25 degrees and sometimes more. The proof is in the idle-speed continuing to increase steadily.
I'll bet your cam-timing is messed up. Since it has already been running, I suggest a compression test. Crank at WOT, all plugs out, enough compression-cycles to get two consecutive shots at or near the same pressure.

BTW
Just to be clear;
>on your timing-tab, from the front of the car, numbers to the left are Advance.
>The #1cylinder is the Driverside front.
> In most cases, you cannot use a dial-back Timing lite on any multi-strike Ignition system
> if your timing lite strobe is doing all of these things;
jumping back and forth, and
missing strobes, and/or
double-strobing; and
you have a magnetic trigger in the Distributor, then;
chances are better than good that the polarity on the pick-up is reversed.