there isn't one, it varies as a function of cam angle due to sliding foot design . if you refer to schrick catalog and compare valve lift to cam lift its about 1.5-1.6. different cam profiles behave slightly differently
thanks for that, I guess what I'm after is the "mean" to help set the valve clearances correctly, as I've got worn stem tops making the feeler gauge useless at the eccentric end, so want to set the clearance at the cam -
You'd need to get a good condition head and check, chances are you won't have a feeler the right size they usually only come on 0.05mm increments so it's either 0.15mm if doing clearance between lobe and foot