318 just started knocking???

If the knock is comming from one cylinder wrist pin or rod bearing, start it up and pull one plug wire at a time. When you change the knock sound you found the source.

The misprint for rocker shaft bolt torque has been in a few aftermarket books for years now. I've never heard of this misprint in a factory service manual before. Anyway...
Correct is 18 ft. lbs. not 30. Too late I know. Good luck with it.