| Years |
CID |
Casting Number: |
Notes: |
| 1955 |
287 |
518037 |
|
| 1956 |
316 |
521560 |
|
| 1957 |
347 |
523293 |
|
| 1958 |
370 |
528456 |
|
| 1959 |
389 |
532000 |
|
| 1960 |
389 |
536387 |
|
| 1961 |
389 |
538181 |
|
| 1961 |
421 SD |
538181 |
no transfer lug |
| 1962 |
389 |
538181 |
|
| 1962 |
389 |
542426 |
Stock Replacement |
| 1962 |
421 SD |
538181 |
no transfer lug |
| 1963 |
326 |
538211 |
|
| 1963 |
389 |
543680 |
|
| 1963 |
421 |
544988 |
|
| 1964 |
326 |
9773153 |
|
| 1964 |
389 |
9773155 |
|
| 1964 |
421 |
9773157 |
|
| 1965 |
326 |
9778840 |
|
| 1965 |
389 |
9778789 |
|
| 1965 |
421 |
9778791 |
|
| 1966 |
326 |
9778840 |
|
| 1966 |
389 |
9778789 |
|
| 1966 |
421 |
9778791 |
Early Year |
| 1966 |
421 |
9772611 |
Late Year |
| 1967 |
326 |
9786339 |
|
| 1967 |
400 |
9786133 |
|
| 1967 |
428 |
9786135 |
4 bolt main |
| 1968 |
350 |
9790079 |
|
| 1968 |
400 |
9790071 |
|
| 1968 |
400 |
9792506 |
Ram Air 4 bolt |
| 1968 |
428 |
9792968 |
4 bolt main |
| 1969 |
350 |
9790079 |
|
| 1969 |
400 |
9790071 |
|
| 1969 |
400 |
9792506 |
Ram Air IV 4 bolt main |
| 1969 |
428 |
9792968 |
|
| 1969 |
303 |
546313 |
|
| 1969 |
400 |
9792968 |
Ram Air V 4 bolt main |
| 1969 |
428 |
545887 |
Ram Air V 4 bolt main |
| 1970 |
350 |
9799916 |
|
| 1970 |
400 |
9799914 |
|
| 1970 |
400 |
9799914 |
Ram Air III ( 4 bolt) |
| 1970 |
400 |
9799991 |
Ram Air IV (4 bolt) |
| 1970 |
400 |
481708 |
4 bolt main |
| 1970 |
455 |
9799140 |
|
| 1971 |
350 |
481990 |
|
| 1971 |
400 |
481988 |
|
| 1971 |
455 |
483677 |
HO 4 bolt main |
| 1971 |
455 |
485428 |
Late HO |
| 1972 |
350 |
481990 |
|
| 1972 |
400 |
481988 |
|
| 1972 |
455 |
485428 |
|
| 1972 |
366 |
(485)212 |
|
| 1973 |
350 |
488986 |
|
| 1973 |
400 |
481988 |
|
| 1973 |
455 |
485428 |
|
| 1973 |
455 |
(490)132 |
SD no transfer lug |
| 1974 |
350 |
488986 |
|
| 1974 |
400 |
488988 |
|
| 1974 |
455 |
485428 |
|
| 1974 |
455 |
(490)132 |
SD |
| 1975 |
350 |
488986 |
Early |
| 1975 |
350 |
500810 |
Late |
| 1975 |
400 |
481988 |
Early |
| 1975 |
400 |
500557 |
Late |
| 1975 |
455 |
500813 |
|
| 1976 |
350 |
500810 |
|
| 1976 |
400 |
500557 |
|
| 1976 |
455 |
500813 |
|
| 1977 |
400 |
568557 |
|
| 1978 |
400 |
568557 |
|
| 1979 |
400 |
568557 |
|
| |
|
|
|
| Notes: |
| All 421/428/455 blocks have a
"TRANSFER LUG" cast into the block near the distributor hole. |
| 1955-1958 blocks had no side motor mounts,
they used a mount under the timing cover |
| All blocks prior to 1964 had the casting
number on the passenger side of the block. |
| 1964 & up have the casting numbers by
the distributor (Except 421's) |
| 1959 thru 1969 blocks have 2 motor mount
holes |
| 1964 was the start of block mounted
starters |
| Starting in 1965, cylinder head oiling
passages were eliminated from the blocks. |
| 1955 thru 1966 have 2 freeze plugs per
side. |
| All the above information was taken from
Pete McCarthy's "Pontiac Musclecar Performance" book. |
