318 Engine stumble

Just to address this first before anything else.

This is pinging at idle. It’s a light ping.

When I put it in gear it gets worse and louder. More consistent.
The car is running 20hg and for some reason it’s idling at 600.
I was checking the springs and weights before this. I pushed them out and forced them to where they were completely out. The last 1/8” was hard and I’m wondering if the distributor puts enough force on them to get them that far. I’m wondering if I stretched the springs and now they are coming in at idle. Doubt it since rpm doesn’t raise up.....in fact it’s too low.

I know at 13° base timing I shouldn’t have this problem. When I was at 15° I didn’t have this problem. So why now...?

What I will do tomorrow is use a piston stop to see if the harmonic Timing mark is off. Can’t hurt to do this anyway as I’m sure the harmonic balancer is original. As old as the chain is....it doesn’t jump around. The engine is completely stock short block. Just a streetmaster, Hei, and a Holley 600 added to it

Any thoughts on the pinging all of a sudden
Learning a lot but not all there?

I’ll be happy just to get it running right. I feel like I’m close