Comp test today revealed issues to address, although not clear how urgent.
Changed plugs and plug wiring after comp test, 351 runs with much more throat.
Cracked exhaust manifold, so it sounds like a Harley.
Here's the cylinder numbers

Radiator
4 5
3 6
2 7
1 8
Driver Passenger

Here's the results
Cylinder Test(psi) Cylinder Test(psi)
4 135 5 135
3 135 6 90
2 120 7 135
1 155 8 135

I am concerned about cyl 6@90, seems like burnt valve (oil in cyl didn't help).
Concerned about 1@155, but have no idea other than crud on exhaust valve.

What should I be worried about, and how urgent, and what to do?

BTW, my 15 year old son helped me throughout the test and plug change. He's getting stoked on real auto stuff.