98 ragtop scary knock ( knew what i was thinkin, didn't know what i was doin)

[BOSS222211]

2 ex wives never drove it and i let a new ( now EX) girlfriend use it for a week while i was away. Anyway it has a bad knock that I cannot seem to pinpoint even with a stethiscope. The second cylinder back on both sides has 90 and 110 compression vs 150 elsewhere. I've removed all belts and pulleys, checked torque converter bolts, changed oil and filter ( I know she ran it off the road and filter was dented) Also in the my garage it decided to puke out the passenger side resonator a collection of dark grey porcelin looking material which my guess is catalyic origin. It almost sounds like something inside the intake manifold.The knock is mostly consistent however when turning the wheeks it can fade away??? I was getting ready to pull the heads when i read about the 700.00 wrench needed to reinstall/. can anyone help me before i pullout my last ten hairs. DOes anyone know a good trustworthy mechanic south of Tampa fla