Correct. If you need more than one turn after the "zero lash" point to reach the specified torque, you'll need to add a shim under the rocker arm bridge.

 

I would recommend torqueing to 18-20ft lbs on each rocker with lifter at lowest position, rotate crank by hand and go through all lifters this way. obviously easier if your bottom intake is off, or try watching valve springs when valve is not opened if you dont wish to remove lower. IMO

 

Yep that's right. Just for referance the thick shims are good for one turn and the thin ones are good for a half turn. So if it takes 1.5 turns to get to torque spec then you'd need a thin shim.

It's been my experiance that for noise reason I like it closer to the 1 full turn than the 1/4 turn.

 

You have to be certain the lifter is on the base circle of the cam; tighten by hand while rocking the rocker til you take up the slack on both sides (pushrod and valve stem) ----- at THAT point put your torque wrench on and torque to 18-20 lb-ft while counting number of turns. It should hit the torque somewhere between 1/4 and 1 turn. If you can't reach zero lash or if it takes less than 1/4 turn, you need longer pushrods. If it takes more than one turn, shim the rocker up until you're less than 1 turn. Each .030" shim reduces the number of turns by about 1/4.

 

The threaded part of a rocker arm bolt is 1.20" long and has 20 threads, so one full turn of the bolt takes it down exactly 0.060". That makes half a turn 0.030".
You'll be aiming for a lifter preload of 0.030"-0.060" which is 1/2 to one full turn past the "zero lash" point. If it takes one to 1-1/2 turns to reach the specified torque, use a 0.030" shim under the rocker arm bridge. If it takes 1-1/2 to 2 turns, use a 0.060" shim.
If you reach the specified torque less than 1/2 a turn past the "zero lash" point, you'll need a longer pushrod.