# R5671A-9 NGK Standard Racing Spark Plug | Genuine NGK Spark Plug

## 🔧 Product Description

**NGK Standard Racing Spark Plug – Part Number: R5671A-9**

NGK racing spark plugs are built for sustained high-RPM, high-temperature competition use, with precious-metal electrodes and cold heat ranges chosen for heavily loaded engines. Racing plugs are application-specific – heat range selection is critical, so confirm the specification for your engine before fitting.

## ⚙️ Key Features

-   Competition-grade construction for sustained high RPM and cylinder temperatures
-   Cold heat range for heavily loaded engines
-   Pure alumina silicate ceramic insulator, providing superior strength and better heat transfer
-   Triple seals prevent leakage

## 📏 Specifications

-   NGK stock number: 5238
-   Thread: Racing Spark Plugs
-   Reach: 19 mm (3/4 in)
-   Hex: 16 mm (5/8 in)
-   Seat: Gasket
-   Terminal: Solid
-   Type: V-Power Non-Resistor

## 🚘 Application

Listed in NGK's application charts for marine, motorcycle, ATV and snowmobile equipment. The chart shows a 0.5 mm gap for these engines, but check it against your engine's manual before fitting.

-   Mercruiser HP900 SC (8 CYL GM BIG BLOCK) – Inboard Engine
-   Mercruiser HP900 SC (8 CYL GM BIG BLOCK, DRY SUMP) – Inboard Engine

## 🔄 Supersession & Cross Reference

NGK's cross-reference tables list this plug against these part numbers.

-   Autolite: 2593, 2613, 3933, 4052, AR3933, AR3933X
-   Bosch: 7529, F3CS, W3C, W3C0, W3CC, W3CO
-   Champion: 687, C59, C59C, C59CX
-   Motorcraft: AG701, AG701C, AG901, AG901C
-   DENSO: 4046, W27ES-U
-   ACDelco: S41XL
-   Accel: 762

## 📦 Condition

-   Brand new genuine product
-   Supplied in original packaging

## Details

- **Price:** 18.0 AUD
- **Vendor:** NGK
- **Type:** Ignition & Controls

## Variants

| Variant | Price | Available |
|---------|-------|-----------|
| Default Title | 18.00 AUD | In stock |

## Images

- R5671A-9 NGK racing spark plug

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> Source: [Sawley's Auto and Marine](https://www.sawleysautoandmarine.com.au/products/r5671a-9-ngk-standard-racing-spark-plug-genuine-ngk-spark-plug)
> Updated: 2026-09-03