Page 845 - 2021-22 Auto Performance_Circle Track

Spark Plug Heat Range/Cross Reference
Thread Heat
Size/Reach Hex Range Autolite Champion E3 NGK Accel Autolite Champion E3
Standard Non-Resistor Spark Plugs
Power/Projected Tip Non-Resistor Spark Plugs
Chevrolet, Chrysler (Wedge), Oldsmobile, Pontiac - Standard Reach - Flat Seat with Gasket
14mm/3/8"
14mm/3/4"
14mm/3/4"
14mm/.460"
14mm/.708"
13/16"
5/8"
13/16"
5/8"
5/8"
Hot
Cold
Chevrolet (Big Block), Chrysler (Hemi) - Flat Seat with Gasket
Hot
Cold
Cold
Chevrolet (Small Block), Ford (Small Block) - Conical/Tapered Seat
Hot
Cold
Chevrolet (Big Block), Ford - Conical/Tapered Seat
Hot
Cold
Ford (Windsor and Big Block) - Conical/Tapered Seat
18mm/.460"
13/16"
Hot
Cold
—
—
AUTAR3935
AUTAR3933†
AUTAR3931
—
AUTAR2592
—
—
—
AUTAR135
AUTAR133
—
—
AUTAR474
AUTAR472
—
—
—
— — — — — — — NGKB8S
AUTAR3934 CHPC61CX E3PE3.103‡ NGKR5671A-8 AUTAR3932† CHPC57CX E3PE3.101‡ NGKR5671A-10
NGK
NGKR5670-6 NGKR5670-8
NGKR5672A-8 NGKR5672A-10
— — —
— —
— E3PE3.107‡
— — NGKR5674-10
— — NGKR5724-8 — — NGKR5724-10
— — NGKAP8FS
—
CHPC63CX
CHPC59CX
CHPC55CX
AUTAR2593
— — — —
— — — —
— AUTAR3911 — —
— — — AUTAR52 — AUTAR50
— — — AUTAR12 — —
— AUTAR94 — AUTAR92
— AUTAR32
CHPC61YC — CHPC57YC —
— — — — — —
—
—
—
—
CHPV63C
CHPV59C
—
—
CHPS59C
CHPS55C
—
—
—
—
E3PE3.102‡
—
—
— — —
— — —
NGKR5673-6 — NGKR5673-9
NGKR5674-6 NGKR5674-8
AUTAR134 AUTAR132
— E3PE3.105‡ CHPV57C —
— — — — AUTAR473 CHPS57C E3PE3.108‡ —
— — — —
—
—
—
—
—
—
E3PE3.104‡
—
—
—
—
—
—
—
—
NGKR5671A-7
NGKR5671A-9
NGKR5671A-11
—
—
—
—
—
NGKR5673-7
NGKR5673-8
NGKR5673-10
—
—
—
—
—
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.
• 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

is imperative that the plug stay cool enough to prevent pre-ignition or electrode destruction, and still remain hot enough to burn off - ed 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
which is too hot can cause pre-ignition and detonation, often resulting in a severely damaged engine.
CIRCLE 2021-22 843 TRACK
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— AUTAR73 — — ——
— —
—
—
—
—
—
—
—
—
ACL0276S-4*
—
—
—
—
—
—
—
—
—
—
—
AUTAR3910†
—
—
AUTAR53
AUTAR51
—
—
AUTAR13
—
—
—
AUTAR93
—
AUTAR33
—
—
—
—
CHPC59YC
—
—
—
—
—
—
—
—
—
CHPRS9YC
CHPS59YC
—
—
—
—
AUT353
CHPJ4C
—
NGKB7S
—
AUTAR72
—
—
NGKR5670-7
—
—
E3PE3.106‡
—
—
—
—
—
—
—
—
—
—
E3PE3.109‡
—
—
—
NGKR5670-5
NGKR5670-9
—
NGKR5672A-9
—
Chevrolet (Big Block), Chrysler (Hemi) - Flat Seat with Gasket
Hot
—
—
—
—
—
—
NGKR5674-7
NGKR5674-9
—
—
NGKR5724-9
—
—
—
Spark Plug Diagnosis Pictures Courtesy of Autolite
Normal Fuel Fouled Detonation Oil Fouled