Ultra 40 Plug Wire Set - BBC HEI

The Moroso Ultra 40 Plug Wire Set for big block Chevy HEI distributors delivers high-performance spark plug wire reliability for engines running under sustained load and high RPM conditions. This eight-cylinder plug wire kit features spiral core construction and 8.65 mm diameter wire diameter, engineered to minimize electromagnetic interference and maintain signal integrity across the power band. The 90-degree plug boots ensure secure connection in tight engine bay configurations typical of big block applications, while the HEI-style terminal interfaces directly with modern ignition systems without adapters.

Spiral core wire construction reduces capacitance loss that can degrade spark energy, particularly important when tuning for maximum ignition performance. The under-header routing design accommodates the tight clearances found in many big block Chevy installations where conventional wire paths interfere with exhaust manifolds or headers. Black insulation resists UV degradation and maintains appearance in engine bays exposed to prolonged sun exposure. At 2.37 lbs, this complete wire set installs without requiring supplemental supports or rerouting existing engine components.

This kit addresses the specific needs of big block Chevy builders, restoration shops, and enthusiasts upgrading ignition systems on carbureted or fuel-injected engines. Whether transitioning from points-based ignition to HEI or replacing worn original equipment wires, the Ultra 40 set provides the connector compatibility and routing flexibility that big block applications demand. The wire set works with factory-style distributors and modern aftermarket HEI units that use the same terminal design standard.