Lifter Shim kit for Modular Engine 4.6/5.4/5.0

These Hardened stainless Steel Black oxide shims are required for most aftermarket cams. To determine if these are needed simply measure the smallest portion of your camshaft lobe (known as the base circle) and compare it to your factory cam. If it is smaller, shims are required. Each shim will account for .025 of undersize base circle, so if you base circle is .050 smaller 2 shims will be required to maintain the same lifter preload. QTY 32 included - simply change quantity to 2 if more shims are needed.