Gm Hei Advance Kit

The GM HEI Advance Kit from MOROSO is a precision mechanical advance component designed for rebuilding and tuning General Motors High Energy Ignition (HEI) distributors. This kit addresses the core timing control system in classic and early-model GM engines, making it essential for enthusiasts restoring original ignition functionality or optimizing engine performance. Whether you're rebuilding a stock distributor or fine-tuning your engine's spark curve, this advance kit delivers the mechanical control needed for precise distributor operation.

This complete mechanical advance assembly includes the centrifugal weights, centerplate, and three spring sets—the three critical components that govern how spark timing advances with engine RPM. The weights spin outward as engine speed increases, moving the advance mechanism and progressively advancing ignition timing to match load and RPM conditions. The three included spring sets provide tuning flexibility; stiffer springs slow advance progression for street engines, while softer springs accelerate timing curve for high-RPM performance builds. MOROSO's precision manufacturing ensures consistent weight tolerances and reliable spring characteristics for repeatable ignition behavior across the entire RPM range.

This kit is ideal for rebuilding worn distributor assemblies in 1970s–1980s GM vehicles or customizing advance curves on performance engines. Professional mechanics and experienced hobbyists benefit from having multiple spring sets on hand to dial in optimal timing curves without purchasing separate components. Installation requires basic distributor disassembly knowledge; the lightweight design (0.11 lbs) and compact dimensions ensure straightforward removal and reassembly. Compatible with all GM HEI distributors, this kit restores critical ignition control and is a foundational upgrade for any GM engine rebuild focused on reliability and drivability.