MACE PERFORMANCE 12MM MANIFOLD INSULATOR FORD FAIRLANE NA NC NF NL AU SOHC INTECH VCT 3.9L 4L I6Exclusive to Mace Engineering, our design registered manifold insulator to suit Ford 6 cylinder engines from EA to AU What are manifold insulators and what do they do? Manifold insulators are a thermal insulating spacer that mounts between your upper and lower intake manifold. Made from a heat blocking composite, our manifold insulators will increase power from your engine by keeping the intake cooler, and increase low end torque by increasing runner