But if you had the rocker covers off to change the intake valve stem seals and you obviously had a "head on" spring compressor to remove the retainers and locks from those intakes, why wouldn't you have checked the valve stem movement on those sus valves when you had the chance? Doesn't really make sense to me at this time why you didn't wiggle those valves in the guides to see how much play there was. That would have either confirmed or eliminated worn guides. And if you were not sure on how much play was acceptable, easy enough to remove a couple more springs from some good bores and compare the valve stem movement on them.
