Yeah I think if I have to shorten the slots, I'm just going to buy the FBO plate as I don't have the time/patience/welding skill to do that myself.

FWIW, this is the Mopar Performance distributor that I got from Summit maybe back circa 2006-ish. I don't think they sell it anymore. Any idea what the vacuum advance is on this?

I'm wondering if I role the timing back maybe 2* to 14* base (34 total), then that might cure the pinging issue. However, I'm wondering what the vacuum advance will do to the idle advance...if it will be too far advanced or not.