Is there some way to gauge whether or not my stock rockers are too loose?
It just seems like they are making more noise than they should, I have tried to tighten them but the bolts won't budge.
91 with over 125k.

Shouldn't have much play at all.
Wouldn't hurt to go through and adjust them all.
Not uncommon with sbc's.

Take out all your sparkplugs, turn the motor by hand, and take off the valve cover.

rotate the motor and feel the rockers. They do loosen up over time.

When one valve starts to go down, the other valve should be tight.

Take out all your sparkplugs, turn the motor by hand, and take off the valve cover.

rotate the motor and feel the rockers. They do loosen up over time.

When one valve starts to go down, the other valve should be tight.

Hopefully I won't get it for asking this, but how do you turn the engine by hand?

Hopefully I won't get it for asking this, but how do you turn the engine by hand?

Put a 1/2 inch drive. 5/8 socket on the balancer bolt. You may need a short extention and a deep sock, or a short socket and a longer extension.

Do it from underneath the car. Does require 2 people. Easy though. the person turning the engine doesn't need to know anything.

By keeping the spark plugs out the odds of doing damage are pretty close to nill.

Hopefully I won't get it for asking this, but how do you turn the engine by hand?
Use the correct (13/16'?) socket on the alternator pulley nut with a 1/2" drive ratchet to turn the altenator. THE BELT WILL TURN THE ENGINE. NO ENGINE DAMAGE WITH THE PLUGS IN OR OUT, BUT IT WILL TURN EASIER WITH THE PLUGS OUT.

RACE ON!!!

Use the correct (13/16'?) socket on the alternator pulley nut with a 1/2" drive ratchet to turn the altenator. THE BELT WILL TURN THE ENGINE. NO ENGINE DAMAGE WITH THE PLUGS IN OR OUT, BUT IT WILL TURN EASIER WITH THE PLUGS OUT.

RACE ON!!!

I didn't mean engine damage, I meant running the risk of damaging the bolt. Some people only have a 12 point socket and it goes on an angle sometimes.

Just caution.