Spark Plug 350 5.7 Indmar/Marine Power/PCM - MR43LTS

- The MR43LTS is a specialty marine-grade spark plug built for reliable performance in 5.7 L small-block Chevrolet engines used by Indmar, Marine Power, and PCM; it features a copper-core, long-reach design with a resistor (2.5–12 kΩ) for reduced radio interference, and a taper-seat, nickel electrodes, and ~0.044″ gap
- Thread specs are 14 mm × 1.25 mm with a reach of 17.25 mm (~0.67″); hex size is 5/8″ (16 mm), insulator height is about 25 mm (~0.98″), and it comes with a taper-cut nickel ground electrode for consistent spark delivery
- Widely recognized as the factory-recommended plug—especially for port-injected 5.7 L F-series and LT1 models—MR43LTS is commonly cross-referenced to AC Delco 41‑932 for platinum alternatives; gap recommendation is typically .045″