Spark Plugs By Year
How to read an AC Delco spark plug nomenclature.
The following matrix of spark plugs used are for AC Delco as installed. Some of these may no longer be readily available or have been superseded by GM and can be used to cross-reference to another brand such as Autolite, Bosch, NGK, Champion, etc.
Year | Engine | AC Delco Spark Plug |
1964 | 194/230 | 46N |
283/327 | 44/45 | |
1965 | 194/230 | 46N |
283/327 | 44/45 | |
396 | 43N | |
1966 | 194/230 | 46N |
283/327 | 44/45 | |
396 | 43N | |
1967 | 194/230 | 46N |
283/327 | 44/45 | |
396 | 43N | |
1968 | 194/230 | R46N |
307 | R45S | |
327 | 44 | |
396 | 43N/44N | |
1969 | 230/250 | R46N |
307 | R45S | |
350 | R44 | |
396 | R43N * | |
1970 | 250 | R46T |
307 | R45 | |
350 | R44 | |
396/402 | R44T * | |
454 | R43T | |
1971 | 250 | R46TS |
307/350 (L65) | R45TS | |
350 (L48)/402 | R44TS | |
454 (LS5) | R43TS | |
1972 | 250 | R46T |
All V8 | R44T | |
* Early in 1970 the 3964290 cylinder head was recast to use the R44T tapered seat plugs so early castings may still use the R43N 'standard' plugs.