Adaptor screws onto original oil filter location and allows rotation of filter to provide clearance for engine swaps and chassis modifications. Fits most Ford small and big block pushrod engines with 3/4-16 thread filter mount. Uses 22mm thread Ford Racing CM-6731-FL820, Motorcraft FL-820, or FL-820S filters for large return flow path and shorter case, can also use Motorcraft FL-500 or FL-500S filter