i always take it off the valve stem but i dunno whats beter. I do know wider is better :thumbsup: If its power on the cheap your after you can go real wide. I dont even use a feeler guage. just twist the valve with your fingers and youll see at what point in the stroke it actually closes. you can take it down till the valves are actually closed most of the compression stroke. But leave atleast 1/4 stroke overlap. only downsides are hard to pull rope and slighly more valve noise. try it on a junk engine first to see if you like it. You will like it :laugh:
Always the valve stem, however, be real careful with "grinding" (assuming you are referring to a power tool?), as you can take of too much material REAL quick. If you do, there is no going back and you will be buying a new one! I prefer to clamp the stem securely and square in a vise and (gently) HAND FILE it. Even with this method you have to be careful and keep checking your lash as you can still take off too much. (Don't ask how I know!:doah
Michael
Michael