Hi Steve-----------The valves must be in the closed position for adjustment. This means that the lobes should be pointing upward. A remote starter is very helpful in turning the engine. You may want to set the valve lash while the engine is cold--drop back a couple of thousandths to .008 intake and .010 exhaust. Then check after the engine has reached maximum operating temperature to see if the gap is at the specified .010 intake and .012 exhaust. It's a lot easier to set the gap cold, and the settings will be more uniform this way. As you become more familiar with this operation, you will be able to set them hot without letting the engine cool too much. Good luck!
Roadman is right on , only I have a bone stock L24 and I just bump the starter untill no. 1 is tdc and the lobes are level wihe the head and the valves are closed and adjust both the intake and exhost then bump to the next in the fireing order , like roadman said do it cold then after driving the car to get it completely warmed up check them again hot. Good luck, Gary Portland Or