The following is an email from a customer: Hello Dennis, Good morning. Hope you’ve had a great summer so far. Quick update for you.  I took on the project to install sleeves on all the spark plugs on my V-10 F-250.  I had originally installed two sleeves (of lesser quality) and found out that the previous owners had also done another one (of lesser quality also).  In all, three spark plugs had blown out of this engine before I decided to replace them all. Â I ordered your Calvan 38900 Ford spark plug thread repair kit and four extra sleeves (inserts) and started working on my truck the last week.

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