Another update:

One night coming home I noticed it was pitch black dark so I left the garage door closed and used the opportunity to check my spark plug wires for arcs. My wires were generic,...

Thank you all for the replies. I thought I'd update since working through this. It took considerable time since there were discoveries over many months.

Discoveries:

1. A spark plug on the...

I have a 1227165 MAF TPI on a 72 chevelle. It runs nice when the maf works. They last about 10 hrs and then give max gm/s at idle and make it run super rich. At idle it shows 23 gm/s instead of...