They had the head completely appart, I assembled it. I think I just checked the guide by moving the valve side to side in the guide minimum play didn't actually took a measurement reading. The shop told me they were good, I've known the owner for many years good honest guy, now he has help which did the work, giving him the benifit of the dought till find the cause. also I put brand new factory valve springs, need to ck. if any are broken?