Buick 225/231 V6 Casting Numbers, Internal Specs For Most Years and Notes
Compiled by Joel Vande Berg
| Year | CID | Liter | Bore | Stroke | Description | Block Casting | Crank Forging | Head Casting |
|---|---|---|---|---|---|---|---|---|
| 1982 | 231 | 3.8 | 3.80 | 3.40 | V6, Even-Fire, Turbo Charged, Crank may have 5/8″ or 3/4″ Pulley Bolt Hole | 25506818 | 1260877 | |
| 25514290 | ||||||||
| 1981-79 | 231 | 3.8 | 3.80 | 3.40 | V6, Even-Fire, Turbo Charged, Crank may have 5/8″ or 3/4″ Pulley Bolt Hole | 25506818 | 1260877 | 25506293 |
| 25506397 | 25504443 | |||||||
| 1978 | 231 | 3.8 | 3.80 | 3.40 | V6, Even-Fire, Turbo Charged, Crank may have 5/8″ or 3/4″ Pulley Bolt Hole | 1254083 | 1260877 | 1257051 |
| 1261438 | 1257125 | 1257722 | ||||||
| 1255674 | ||||||||
| 1981-79 | 231 | 3.8 | 3.80 | 3.40 | V6, Even-Fire, Crank may have 5/8″ or 3/4″ Pulley Bolt Hole | 25506818 | 1260877 | 25506293 |
| 25506397 | 1257125 | 25504443 | ||||||
| 25505554 | 1255674 | 1262098 | ||||||
| 25514290 | 1261377 | |||||||
| 1261787 | ||||||||
| 1978-77 | 231 | 3.8 | 3.80 | 3.40 | V6, Even-Fire, Split Rod Pin Crank | 1254083 | 1257125 | 1257051 |
| 1255862 | 1260877 | 1257661 | ||||||
| 1261438 | 1255674 | 1257722 | ||||||
| 1977 | 231 | 3.8 | 3.80 | 3.40 | V6, Odd-Fire, Straight Rod Pin Crank, with Integrated Dist. Drive | 1254083 | 1255645 | 1257051 |
| 1255862 | 1255846 | 1257661 | ||||||
| 1261438 | 1357898 | 1257722 | ||||||
| 1378354 | ||||||||
| 1976-75 | 231 | 3.8 | 3.80 | 3.40 | V6, Odd-Fire, Straight Rod Pin Crank, with Non-Integrated Dist. Drive | 1249432 | 1357898 | 1249175 |
| 1378351 | 1254164 | |||||||
| 1378354 | ||||||||
| 1967-74 | 225 | 3.7 | 3.75 | 3.40 | V6, Odd-Fire, Kaiser Jeep Corp/AMC | 1358435 | 1357898 | 1358676 |
| 1396736 | 1368767 | |||||||
| 1381623 | B-1376348 | |||||||
| 1375162 | ||||||||
| 991503 | ||||||||
| 1963-6 | 225 | 3.7 | 3.75 | 3.40 | V6, Odd-Fire, FWD/RWD w/ one barrel Carb | 1396736 | 1327898 | 1358767 |
| 1963-65(? | 225 | 3.7 | 3.75 | 3.40 | V6, Odd-Fire, FWD/RWD w/ one barrel carb | 1358435 | ||
| 1961-63 | 198 | 3.2 | 3.625 | 3.20 | V6, Odd-Fire, FWD/RWD Buick applications only | 1349430 |
The remainder of this reference is written and compiled by Jamie Carter and maintained by the Early CJ-5 Page.
225 Intake casting numbers:
- 1 barrel : 1381552
- 2 barrel : 1378704
- there may be others…
225 V-6 engine id codes: Buick special 64-67 (1 and 2 bbl.)
- 1964 = KH [between branches of right exhaust manifold]
- 1965 = LH [engine number on the right front face of the crankcase, just below cylinder head]
- 1966 = MH [as '65 above]
- 1967 = NH [as '65 above]
…so the codes are either on the side or front of the block just under the cylinder head.
(I have heard rumors of a few engines produced in ‘63).
All are listed as 9.0-1 comp. ratio.
The engine codes seem to indicate that the first letter is the engine year, while the second letter is the comp ratio (9.0-1). The two letters together identify this engine as a 225 V-6, as the same year letter was used by Buick for all engine types ‘64-’71 (v-6, v-8) but the second comp ratio code letter varied between different engine types with the same comp ratio (i.e., a ‘64 V-6 comp ratio 9.0-1 is a “KH”, while a ‘64 300 V-8 comp ratio 9.0-1 is a “KL”).
The front of the engine is to the right, the block casting # is on the rear, the engine # is on the right bank.
Thanks to Joel Vanguard for the picture of V6 number locations
From “Service Manual Jeep Universal Series“;
“The engine code number shown in Fig A-4 is provided to identify the Dauntless V6-225 engine. The meaning of the coded letters and numbers that are stamped on the right front face of the crankcase, just below the rocker arm cover, between exhaust manifold ports, is given below:
Letter to designate market:
- M-Military
- E-Export
- D-Domestic
Letter to designate year Built:
- N-1967
- P-1968
- R-1969
- S-1970
- T-1971
Letter to designate Engine Compression Ratio:
- H-V6-225 9.0 to 1 C.R. (2bbl carb)
- Y-V6-225 9.0 to 1 Marine (Low Profile) (2 bbl carb)
- Z-V6-225 9.0 to1 Marine (High Profile) 2bbl carb
- K V6-225 7.6 to 1 (2bbl carb)
- L V6-225 7.4 to 1 (2bbl carb)
The next three numbers are then the day of the year noted in the second position.
In 1965, some Jeep V-6’s are listed as coded “KLH” (and maybe’64 or ‘66 engines as well, still trying to research this).
All Buick 231 block casting numbers from my info begin with the numbers 124, 125, 126, or 255.
(last update 12-Apr-04). Information from various sources named and unnamed, some personal opinions are expressed. Not responsible for errors, as the weeding of the garden of knowledge to find the flower of truth is a never-ending quest.
jdc. & ahs.