Holley Date Codes
Four Digit Date Codes
First Three Digits--Day of Year
Day Code
Non Leap Year | Day Code
Leap Year | Month of
Production |
| 001-031 | 001-031 | January |
| 032-059 | 032-060 | February |
| 060-090 | 061-091 | March |
| 091-120 | 092-121 | April |
| 121-151 | 122-152 | May |
| 152-181 | 153-182 | June |
| 182-212 | 183-213 | July |
| 213-243 | 214-244 | August |
| 244-273 | 245-274 | September |
| 274-304 | 275-305 | October |
| 305-334 | 306-335 | November |
| 335-365 | 336-366 | December |
Fourth Digit--Year
| 1 | 1961/1971/1981/1991 |
| 2 | 1962/1972/1982/1992 |
| 3 | 1963/1973/1983/1993 |
| 4 | 1964/1974/1984/1994 |
| 5 | 1965/1975/1985/1995 |
| 6 | 1966/1976/1986/1996 |
| 7 | 1967/1977/1987/1997 |
| 8 | 1968/1978/1988/1998 |
| 9 | 1969/1979/1989/1999 |
| 0 | 1970/1980/1990/2000 |
Three Digit Date Codes
First Digit--Year
| 1 | 1961/1971 |
| 2 | 1962/1972 |
| 3 | 1963 |
| 4 | 1964 |
| 5 | 1965 |
| 6 | 1966 |
| 7 | 1967 |
| 8 | 1968 |
| 9 | 1969 |
| 0 | 1970 |
Second Digit--Month
| 1 | January |
| 2 | February |
| 3 | March |
| 4 | April |
| 5 | May |
| 6 | June |
| 7 | July |
| 8 | August |
| 9 | September |
| 0 | October |
| A | November |
| B | December |
Third Digit--Week
| 1 | First Week |
| 2 | Second Week |
| 3 | Third Week |
| 4 | Fourth Week |
| 5 | Fifth Week |