- Ignition & Electrical
- Spark Plugs
- Allstar Performance Spark Plug Indexing Shims
Indexing Shims
Allstar Performance's stackable shims index spark plugs at 30 Degree intervals up to 360 Degrees properly positioning ground strap in cylinder head for a lot more power and clearance between spark plug and piston. Shims are purposed for use with 14mm flat seat spark plugs only. Package of 24 shims contains 12 silver 60 Degree, and 12 black 90 Degree.