Originally Posted by Hotrod Lincoln
The simplest way to tell if you're working on intake or exhaust valves is to look at the corresponding manifold runner. Other than the very end valves front and rear (which are both exhaust, BTW), two valves will share a single manifold runner. Counting from the front, here's the layout:

E-I-I-E-E-I-I-E-E-I-I-E

The pistons on two cylinders reach TDC at once, one on compression, the other on exhaust. These are known as "companion cylinders". Here's the companion cylinder pairs:

1-6
2-5
3-4

To get an accurate position for valve adjustment, watch the valves on the companion cylinder to the one you're about to adjust. As one cylinder reaches the top of the exhaust stroke, the exhaust valve will be closing, and the intake will be starting to open. This is known as "rocking". At the same time, the companion cylinder will be at the top of its compression stroke with both valves closed. Turn the engine clockwise at the harmonic balancer, either by putting the vehicle in gear and rolling it forward, or using a socket on the crankshaft pulley bolt, and watch the valves. Watch the #6 valves. When #6 is rocking, adjust intake and exhaust on #1. Continue until all the valves are adjusted. It will require two turns of the crankshaft to adjust the valves on all six cylinders. Here's the sequence:

Rock #6, adjust #1
Rock #2, adjust #5
Rock #4, adjust #3
Rock #1, adjust #6
Rock #5, adjust #2
Rock #3, adjust #4

To adjust hydraulic lifters, back the rocker nut off until there is plenty of slack in the pushrod with the cylinder at TDC on the compression stroke, then tighten the nut slowly until all the slack is gone. If the pushrod turns easily, there's still some slack. Once the slack is gone, turn the nut another 3/4 turn. Adjust both valves before moving the engine to the next TDC position. Good luck!
Jerry

When you state rock, can you explain what does that mean?