I've been told sam knows 4 valves quite well.I am considering that option.It's going to a shop we take the lincoln mark iv or whatever number it is.Bitemark,I never got to run the compression test today,the fitting didnt want to screw into the sparkplug threads but just testing it without having the tester screwed in i got a equal reading on all cylinders,I'm not gonna go by it since it wasnt properly done.