Difference with spark plugs

[Ian Williams]

The oil loss was nothing to do with the head Jon, Bob was driving a clapped out old car with an early head but it did not foul plugs, he was later driving a slightly less clapped out car with a later head but is did foul, I also suspect he had the wrong plugs in the later head and probably poor mixture as well. I have used Ruby head's extensively and with the right plug and correct mixture there no real issues in my experience, I do agree late heads are more prone to oiling plugs in a worn engine.