Sierra distributor with aluminum housing construction was designed as a direct replacement for late model GM EST distributors. • Meets or exceeds SAE J1171 standards• Includes steel gear, which is compatible with flat tappet or hydraulic roller cams• Reliable high signal-strength trigger system• Ball bearing and bushing combination provides maximum timing stability and a long life• Fits: GM V6 engines with Delco EST ignition HEI Meets or exceeds SAE J1171 standards Includes steel gear | Delco HEI Distributor For V6 GM Engine