Hey everybody. I am putting in some umbrella valve seals tonite and was looking for some information. By looking at them, I thought it would be pretty straight forward, but I just read an article on them that says they ride up and down with the stem. Do the seals need to go on a certain place on the stem when I install them? I don't want to put them too high and have them not seal or too low and have them get annihilated when they get slammed against the head. Is it sufficient to put the seal on the stem, up against the head with the valve closed? BTW, I do have the heads off if that makes a difference. I was going to do the seals while I have the heads off. Thanks!!