Page 527 - 2022-23 Auto Performance Open Wheel Catalog

Spark Plug Heat Range/Cross Reference
Thread Heat Standard Non-Resistor Spark Plugs Power/Projected Tip Non-Resistor Spark Plugs
Size/Reach Hex Range Autolite Champion E3 NGK Accel
Chevrolet, Chrysler (Wedge), Oldsmobile, Pontiac - Standard Reach - Flat Seat with Gasket
Hot — — — — —
Autolite
—
AUTAR73
AUTAR72
—
—
—
AUTAR3911
AUTAR3910 †
—
—
—
—
AUTAR53
AUTAR52
AUTAR51
AUTAR50
—
—
—
AUTAR13
AUTAR12
—
—
—
—
AUTAR94
AUTAR93
AUTAR92
—
AUTAR33
AUTAR32
—
Champion E3
— —
— —
— —
— —
— —
— —
CHPC61YC —
CHPC59YC E3PE3.106 ‡
CHPC57YC —
— —
— —
— —
— —
— —
— —
— —
— —
— —
— —
— —
— E3PE3.107 ‡
— —
— —
— —
CHPRS9YC —
— —
NGK
NGKR5670-5
NGKR5670-6
NGKR5670-7
NGKR5670-8
NGKR5670-9
—
NGKR5672A-8
NGKR5672A-9
NGKR5672A-10
—
—
—
—
—
—
—
—
—
NGKR5674-6
NGKR5674-7
NGKR5674-8
NGKR5674-9
NGKR5674-10
—
—
NGKR5724-8
— — — —
14mm/3/8" 13/16" AUT353 CHPJ4C — NGKB7S
— — — NGKB8S
Cold — — — —
Chevrolet (Big Block), Chrysler (Hemi) - Flat Seat with Gasket
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
ACL0276S-4 *
—
—
—
—
—
—
—
—
—
—
—
—
—
—
Hot 14mm/3/4" 5/8"
Cold
AUTAR3935 — — NGKR5671A-7
AUTAR3934 —
E3PE3.103‡ NGKR5671A-8
AUTAR3933 †
AUTAR3932 †
AUTAR3931
CHPC59CX
CHPC57CX
—
E3PE3.102 ‡
E3PE3.101 ‡
—
NGKR5671A-9
NGKR5671A-10
NGKR5671A-11
—
—
—
—
—
—
—
—
Chevrolet (Big Block), Chrysler (Hemi) - Flat Seat with Gasket
14mm/3/4" 13/16"
Hot — — —
AUTAR2593 — —
AUTAR2592 — —
— — —
— — —
— — —
Cold — — —
Chevrolet (Small Block), Ford (Small Block) - Conical/Tapered Seat
Hot — — —
14mm/.460" 5/8"
— — — NGKR5673-6
AUTAR135 CHPV63C — NGKR5673-7
AUTAR134 — E3PE3.105 ‡ —
AUTAR133 CHPV59C E3PE3.104‡ NGKR5673-8
AUTAR132 CHPV57C
Cold — —
— NGKR5673-9
— NGKR5673-10
Chevrolet (Big Block), Ford - Conical/Tapered Seat
Hot — —
— —
14mm/.708" 5/8" AUTAR474 CHPS59C
—
—
—
—
—
—
—
—
—
—
—
CHPS59YC E3PE3.109‡ NGKR5724-9
— — NGKR5724-10
— — —
— — —
— — NGKAP8FS
— — —
AUTAR473 — E3PE3.108‡
Cold AUTAR472 CHPS55C —
Ford (Windsor and Big Block) - Conical/Tapered Seat
Hot — — —
18mm/.460" 13/16" — — —
Cold — — —
Important Note: Use cross reference chart as a guide only. Due to differences in design and material, plugs listed in cross reference are not exactly alike.
* “Shorty“ spark plug for added header clearance, sold in 4-pack. ‡ E3 DiamondFIRE fixed gap spark plugs cannot be adjusted.
† Special Autolite Racing "X" style electrode spark plug that alleviates piston/spark plug clearance issues is also available; simply add “X” to end of part number.
TECH TIP
• Determine the thread diameter, length (reach), and whether tapered or gasket (flat) seat. • Select gap style.
• Select heat range.
• Adjust fuel mixture and spark advance timing for maximum performance.
Spark Plug Diagnosis
Pictures Courtesy of Autolite
• Inspect plugs and pistons for evidence of detonation, abnormal combustion, or excessive temperatures.
• Stay with the same plug type after final heat range selection unless major modifications have been made (increasing the horsepower or operating range).
SPARK PLUG HEAT RANGE TECH
A spark plug’s Heat Range, defined as the measure of how fast the tip of the plug dissipates combustion heat, can range from as low as 500°F to as high as 2,500°F. Manufacturers offer plugs in many heat ranges, from cold through medium hot, to very hot. It is imperative that the plug stay cool enough to prevent pre-ignition or electrode destruction, and still remain hot enough to burn off combustion deposits that form at the firing tip. A plug that is excessively cold or hot for the application in question will eventually cause the engine to misfire. When working with an engine that is stock or mildly modified, it is often best to use the plug recommended by the car manufacturer. However, if the compression ratio has been altered, a different heat range plug may be required. Many racers rely upon their engine builder for plug heat range recommendations. If a racer
is unsure of the correct heat range to use, it is always recommended to “stay on the safe side” and use a colder plug. A switch in heat range can change the temperature of the spark plug tip by 70-120°F. If the plug selected is too cold, it will eventually foul and misfire, but it will not damage the engine. A plug which is too hot can cause pre-ignition and detonation, often resulting in a severely damaged engine.
2022-23 PARTS AND ACCESSORIES
525
Normal
Fuel Fouled
Detonation
Oil Fouled