I just picked up a 318 and two cylinders have low combustion. Since there were signs that the engine was rebuilt fairly recently, it led me to check the valve lash to see if the valves are seating properly. Unfortunately I don't know the lash settings cause I don't know what kind of Cam I have.

Honestly.....when i first took the car out of storage I could hear valve train pingin'. I thought that was a bad thing so I tightend them down till they quited up. Hopefully I didn't burn out any valves or fry my cam.