NOS AC R46S Spark Plug – GM #5613879

Description:

🔧 Part Overview

• ACDelco Part Number: R46S

• GM Part Number: 56138792

• Type: Non-resistor copper core spark plug

• Thread Size: 14mm x 1.25mm

• Seat Type: Tapered

• Reach: Approx. 19mm (0.75")

• Hex Size: 5/8" (16mm)

• Terminal: Fixed

• Electrode Material: Copper core with nickel alloy ground electrode

• Gap: Typically 0.035"

• Country of Origin: Typically marked “Made in USA”

• Special Feature: Some NOS variants feature green rings and knurled shells, known as “ACNITER” plugs

🚗 Specific Applications

The R46S plug was widely used in:

• 1970s Chrysler and Plymouth V8 engines, including:

  • Chrysler Newport, Cordoba, Town & Country

  • Plymouth Fury, Gran Fury, Sport, Salon

• GM small-block and big-block V8s (305, 350, 400, 454 CI)

• Marine engines (MerCruiser, OMC)

• Industrial and agricultural engines

• Classic hot rods and performance builds using 14mm tapered seat heads