others will know better on that Do some guides have a groove for that bump on the ID?
if you cna check the spring sprung and unsprung length I would if In there. if the head work or the valve becoming hammered in to the seat or lapped in, repositions the valves vertically, then any difference results in that keeper groove being further from the spring lands.. it loosens the spring and that can cause valve float, you can check for coil bind by inserting strips of paper.. I found this to be more important than I first realized. others might have actual specs of proper sprung and unsprung length. and its possible to check the springs with the correct tools to measusre tension at certain lenghts. and that may be specified.
without knowing more I'd just add thin washers and check that the coils arent; binding but there may be ways to be more precise and exacting. if back together and you rev it up and if you hear valve float I'd fix that or it can destroy the cam in short order. Keep your ears tuned for any clicking noises near your redline.
in my case I rebuilt an engine then it happened and my cam got destroyed. I removed two pushrods and a plug and drove it home with the funny noise that made.. it did work.
after a second new cam I heard the sound again but this time I started adding thin washers.. what suprised me was that the springs were not loose or anything very visual,,
Just a thin washer of maybe 10 - 20 thou got rid of all my valve float and I run it up to about 6500 This made me more preceptive of the spring tension causing an issue. I had used new stock springs, It was a volvo but I doubt the problem is very specific unless its an overhead cam.
