If you have the intake and carb off, then it is super easy to view and understand. But first you have to tighen down the rocker shafts and have all the rockers loose and the plugs out of the engine. Then you need to be able to rotate the engine without the ignition being on
Like at the relay. When the intake is going up, the exhaust will start going down. The intake will then close all the way once the exhaust goes down a bit. Do a ruff setting on the intake say at 25 thou or so. Then slowly rotate a bit more and as the intake starts to go down, the exhaust comes up, keep rotating untill it is close and go a bit more. Then set the exhaust around 25 thou. Keep in mind that with a 621 lift cam, if you do all the same side the cam is stressed some with the open pressure it is recieving. So the cam card does help in the order of adjustments to some degree. But keeping a balance is actually all you need to remember as to not cause alot of stress to one certain area at once.
With the intake off, or just watching your push rods go up and down, you can see where and when you will be able to make your adjustments. Since once the lifter has went over center of the cam, the valve is closing and once closed is when you adjust. After you do this a few times, you will be a pro at it. Parts will have to break themselves in to a certain degree, so even after you get down to 18 thou, you may have to do a final adjustment after a few miles or minutes of run time. Adjusting cold, you may want everything loose for start up like 26 or so then after warm and at temp, bring it to the 18 you want. Also changing your vavle setting up or down will give more bottom or top end . Some tune tight to get more on top and some will run 32 thou just for bottom end et.
