Spark Plugs By Year

How to read an AC Delco spark plug nomenclature.

CHEVELLESTUFF  All Rights Reserved

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 Some of these may no longer be readily available or have been superseded by GM and can be used to cross-reference to another brand such as Autolite, Bosch, NGK, Champion, etc.

YearEngineAC Delco Spark Plug
1964194/23046N
 283/32744/45
1965194/23046N
 283/32744/45
 39643N
1966194/23046N
 283/32744/45
 39643N
1967194/23046N
 283/32744/45
 39643N
1968194/230R46N
 307R45S
 32744
 39643N/44N
1969230/250R46N
 307R45S
 350R44
 396R43N *
1970250R46T
 307R45
 350R44
 396/402R44T *
 454R43T
1971250R46TS
 307/350 (L65)R45TS
 350 (L48)/402R44TS
 454 (LS5)R43TS
1972250R46T
 All V8R44T
   
   

* 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.