Professional Spark Plug Thread Repair Kit. This thread repair kit is designed to repair two valve modular cylinders heads, address a regularly occurs damaged heads from blown spark plugs, replacing inserts This cylinder repair tools is complete, specialty design, precise and perfectly adapted. The helicoil kit of choice for tool enthusiasts and industry professionals alike Complete and Excellent Quality. The drills, taps and line up guide are made of high quality thickened steel, individual pieces are highly tempered, with strong strength,sharpness and maximum durability 8 M141.25 inserts has high hardness and the surface is also treated with black oxidation to prevent corrosion and rust, more robust than ordinary helicoils. Permanent Repair Tools. compatible with Ford years 1996 to 2003, Part No. 389100 Replacement Inserts. The kit compatible with to repair Ford modular cylinder heads on 4.6L, 5.4L and 6.8L 2Valve SOHC engines NOT for 3V engines or DOHC. This permanently fixes that situation with the threads in the cylinder heads, thread repair inserts have stronger threads than the originals. Out of The Box. This is an efficient and fast spark plug repair kit that saves downtime and cost effective, makes working in tight spaces more comfortable With this rethreading kit, Instead of having to pull the cylinder head off andor replace the head, Makes this intimidating job a breeze. Convenient to Use. This spark plug tool kit is very useful and easy to use, Follow the instruction manual and video guides that show how to repair your modular cylinder head and install the inserts, ensures the job can be done quickly and accurately Make sure you follow each step and keep the cylinder cleaned out when making this repair