#12 An Filter Block Off

The Peterson Fluid #12 AN Filter Block Off is a bolt-on oil filter adapter and block-off designed for GM small-block engines equipped with a bowtie emblem. This aluminum block-off plate features a 12 AN male inlet connection and black anodized finish, providing a clean alternative to traditional oil filter configurations in high-performance engine builds. The adapter enables flexible plumbing arrangements for custom cooling systems, remote filter mounting, or closed-loop oil circulation setups common in racing and specialized automotive applications.

Constructed from aluminum with black anodized protection against corrosion, the block-off measures 4.55 x 1.9 x 4.85 inches and weighs 0.73 lbs. The 12 AN male inlet threads directly into aftermarket oil coolers, sandwich adapters, or remote filter housings, eliminating the need for the stock filter canister. The anodized finish resists oxidation in both street and track environments, maintaining appearance while providing durable surface protection. Peterson Fluid's engineering background ensures precise thread specifications and reliable seal surfaces critical for maintaining system integrity under varying operating pressures.

This block-off serves engine builders, racing teams, and performance enthusiasts customizing GM small-block cooling systems. Whether transitioning to an external oil filtration setup, installing an engine oil cooler, or consolidating plumbing in engine bay space-constrained builds, the 12 AN adapter provides a compact, aluminum solution compatible with industry-standard hose fittings and sandwich-style filter adapters. Compatibility is limited to GM bowtie block variants; verify engine block configuration before purchasing to ensure proper fitment.