Racing Spark Plug Cross Reference Chart
Autolite, AC Delco & Champion to NGK
Autolite Racing | AC Delco | Champion | NGK | NGK Stock Number |
AR12 | 40TS | RV9YC | R5674-7 | 5034 |
AR13 | | RV9YC | R5674-6 | 4449 |
AR23 | | RV9YC | BPR6FS | 2623 |
AR24 | | RV12YC | BPR6FS | 2623 |
AR25 | | RV15YC4 | UR4 | 6630 |
AR32 | | RF9YC | AP8FS | 2227 |
AR33 | | RF9YC | AP7FS | 2127 |
AR50 | | N59YD | R5672A-10 | 3395 |
AR51 | 436XLS | N61YD,N6YC | R5672A-9 | 7405 |
AR52 | 440XLS | N63YD,N7YC | R5672A-8 | 7173 |
AR53 | | N9YC | BP6ES | 7333 |
| C44S | | R5670-5 | 2298 |
| 44S | | R5670-5 | 2298 |
| 45S | | R5670-5 | 2298 |
| 46S | | R5670-5 | 2298 |
AR72 | | J12YC | R5670-7 | 2891 |
AR73 | R43S,43S | J12YC | R5670-6 | 2746 |
AR74 | M43S | J12YC | R5670-6 | 2746 |
AR92 | | S57YC | R5724-10 | 7993 |
AR93 | | S59YC | R5724-9 | 6434 |
AR94 | | S61YC | R5724-8 | 4175 |
AR103 | | RS9YC | BPR6EFS/TR6 | 3623 |
- | | RF10C | AR6FS | 3323 |
AR131 | | V55C | R5673-10 | 4050 |
AR132 | M90 | V57C | R5673-9 | 3442 |
AR133 | | V59C | R5673-8 | 3249 |
AR134 | MR41T | V63C | R5673-8 | 3249 |
AR135 | | V63C | R5673-7 | 4367 |
- | | RV8C | R5673-6 | 4256 |
- | | N3C | R5671A-7 | 4091 |
AR472 | | S57C | B9EFS | 1085 |
AR473 | | S59C | B9EFS | 1085 |
AR474 | | S61C | B8EFS | 1049 |
AR764 | | RS12YC | TR5 | 2238 |
AR2592 | | C59 | R5671A-10 | 5820 |
AR2593 | | C61 | R5671A-9 | 5238 |
AR2594 | | N2C | B9ES | 2611 |
AR3910 | | C59YC | R5672A-9 | 7405 |
AR3911 | 440XLS | C61YC | R5672A-8 | 7173 |
AR3923 | | RC9YC | BKR6E | 6962 |
AR3924 | | RC12YC | FR5 | 7373 |
AR3931 | | C55C | R5671A-11 | 6596 |
AR3932 | S40XL | C57CX | R5671A-10 | 5820 |
AR3933 | S41XL, 436XLS | C59CX | R5671A-9 | 5238 |
AR3934 | 41XL | C61CX | R5671A-8 | 4554 |
AR3935 | | C63C | R5671A-7 | 4091 |
| | | | |
AC Delco to NGK
AC DELCO | NGK PN | NGK Stock Number |
42S | R5670-6 | 2746 |
42TS | R5674-6 | 4449 |
436T | R5673-9 | 3442 |
436TS | R5674-9 | 6468 |
438T | R5673-8 | 3249 |
438TS | R5674-8 | 5657 |
438XLS | R5672A-8 | 7173 |
| R5670-6 | 2746 |
43TS | R5674-6 | 4449 |
440T | R5673-7 | 2817 |
R42S | R5670-6 | 2746 |
Heat Range Reference
- NGK Heat Ranges - The larger the number after the dash the colder the plug is. Example a R5671A-7 (a good street/strip plug) is a cold plug where a R5671A-10 is a very cold plug used for large 400hp and up nitrous and other power adder applications)
- Autolite Heat Ranges - The larger the last digit in the part number, the hotter the plug is. Example a AR3935 (good street/strip plug) is hotter than a AR3932 plug which is very cold used for lots of nitrous.
- Champion Heat Ranges - Typically Champion numbers in the same series the larger the number the hotter the plug.
Additional Spark Plug Related Resources