442 BRO's Engine Info

By the 1965 model year, Oldsmobile had the answer, by adding 35 additional horsepower. The General Motors brass were swayed by the success of the Pontiac GTO, so they relented on their decision to keep big blocks out of the mid-size cars. The 65 Cutlass 442 could now be equipped with a de-stroked version of Oldsmobile's monster Stage II 425 Rocket V8. Apparently modified to keep within the revised GM bounds restricting mid-size cars to engines of 400 cubic inches or less, this new 442 powerplant measured out at 400 cubic inches on the nose. Using what Hot Rod magazine described as a "moderate" 10.25:1 compression ratio, the 442's Rocket engine produced a claimed 345 horsepower and an amazing 440 pound-feet of peak torque at 3200 rpm. There's no substitute for cubes.

Designed for heavy-duty use, the engine offered such hot rod parts as forged steel crankshaft and connecting rods, light, stamped steel rocker arms with tubular pushrods, plus 2.0-inch intake and 1.625-inch exhaust valves. All of this good stuff, to use the words of Hot Rod, "contributed to vigorous and long-lasting health."

The short stroke 1965-67 400s are awesome engines. The early 400 engines rev higher than any other big block. They will rev higher than a 425. They have less piston mass. These things will turn almost 7000 RPM.

With the big-block engine under the hood the 442 had quickly come into its own. Oldsmobile still advertised the broad range of its vehicles with the mildly provocative slogan: "Pick the Rocket to fit your pocket!" But with the beefier engine, 442 now meant 400 cubic inches, 4-barrel carburetor and 2 exhausts.

A series of W30 options available on the 442 would do nothing but enhance the reputation of the car as the years passed. The first of these added a Tri-Power-like triple two-barrel carburetor set-up and forced cold-air induction which delivered what Olds said was 360 horsepower. Others suggest the true horsepower figure was more like 400. Before the demise of the 442, it would be equipped with a 455-cubic inch V8 of monstrous proportions that only made its legend more stellar.

The big and small block engine types are almost identical, with the big block having a higher deck than the small block. The bore centers are the same, since the only differences between the small-block and big-block Olds blocks are the deck height (9.33" and 10.625", respectively) and the main journal size ( 2.5" and 3.0"; diesel 350 used BB size mains, however ).

Many internal parts interchange, but it is best to keep the big block parts on the big block and the same for the small block.

The engines were sometimes named, and this was printed on the air cleaner label or sticker. Mid 60's 425s were known as Super Rockets. Some featured Ultra High Compression on their labels.

Quick Identification:

The large oil fill tube on the front of the engine, sticking up from the timing chain area, is a dead giveaway that it is an Olds engine.

Engine code on the oil filler tube.

400 V8 345 4-BBL MT 10.25:1 QW

400 V8 345 4-BBL AT 10.25:1 QR

400 V8 360 3 X 2's MT 10.25:1 QZ

The distributor is found at the back of the block and it does not go through the intake manifold, but right into the block. Also the spark plugs will be above the exhaust manifolds with no need for heat shields.

The Block Code and/or Head Code can give you an idea, but some codes cover many years. The casting number is ususally nearby. Other than that, there is no method of determining the year of manufacture of an Olds block.

The valve covers are a distinctive shape. Straight running front to rear, with an arc connecting each end of the two lines, to define front and rear. From their sealing surface, the covers are curved as they meet their top. The top of the covers are flat, like someone cut off the curved top.

The thermostat cover/radiator hose has a special molded in bypass pipe for the waterpump.

The day of the year of manufacture is the big number right by the distributor hole.

Original paint color can help identify an engine, or further identify it. However, since paint is easily changed, it should be used as supporting evidence, not as absolute indication of engine lineage.

The VIN derivative stamping or engine unit number is on the left most side of the block or head, on the driver's side, just below the cylinder head, toward the front, behind the power steering pump.. The pad is part of the engine and will indicate the year of manufacture, but that is usually rusted beyond recognition, and it can be changed by restamping. Basically it IDs the car in which the motor was originally installed. It can provide some circumstantial info but not a positive ID.

( Note: If the engine was replaced under warranty, the pad may be blank. Rubbing alcohol and Q-tips help to remove the grime and grit from the stamping. )

1964-67 V-8 Engine:

Code is stamped on the right cylinder head. Unfortunately, this only applies to what was originally the passenger side head. This code consists of a prefix letter (330 V-8=T (1964-65) or W (1966-67), 400 V-8 = V), then a production sequence number, followed by a suffix code letter ( L = Low compression, E = 2-bbl export, G = High compression, H = 4-bbl export ). A 2-letter code on the oil filler tube identified the engine.

Oldsmobile Generation 2 Engines:

3.1 330

3.1.1 Jetfire Rocket

3.2 400

3.2.1 4-4-2 Rocket

3.3 425

3.3.1 Super Rocket

3.3.2 Starfire

3.3.3 Toronado Rocket

Generation 2:

The second generation of Oldsmobile V8s was produced from 1964 through 1990. Most of these engines were very similar, using the same bore centers, although "big-block" versions were produced with a 10.625 in (269.9 mm) deck height rather than 9.33 in (237 mm). Big-block and Diesel versions also used a larger 3.0 in (76.2 mm) instead of 2.5 in (63.5 mm) main bearing journal for increased strength. All generation-2 small-block Olds V8s used a stroke of 3.385 in (86 mm). The big-block engines initially used a forged crankshaft with a stroke of 3.975" for the 1965-1967 425 and 400 CI versions; starting in 1968, both the 400 in³ and the 455 in³ big blocks used a stroke of 4.25 in (107.9 mm), with crankshaft material changed to cast iron except in a few rare cases.

These engines, while being a wedge-head, had a unique combustion chamber that resulted from a valve angle of only 6°. This was much flatter than the 23° of the small-block Chevrolet and 20° of the Ford small-block wedge heads. This very open and flat chamber was fuel efficient and had lower than average emissions output. It was the only GM engine to meet US emission standards using a carburetor all the way up to 1990.

400:

The 400 in³ ( 6.6 L ) version was the second tall-deck "big-block" Olds. Two distinct versions of the 400 CID engine were made:

1965 through 1967 Early 400's used a slightly over-square 4.000 in (101.6 mm) bore and 3.975 in (101.1 mm) stroke. All the pre-1968 engines used a forged steel crankshaft.

1968 and 1969 400's shared the Olds big-block standard 4.25 in (107.9 mm) stroke with the 455 but used a very undersquare 3.87 in (98.3 mm) bore to comply with GM's displacement restrictions in the A-body cars and reduce tooling costs. This Later 400 is considered by many enthusiasts to be less desirable because of the powerband characteristics induced by this exceedingly undersquare format, and the fact that the crankshafts were now made of less durable cast iron material. Early 400's used the same forged steel crankshaft as the 425's, while the Later 400's used the same cast iron crankshaft of the 455's, with rare exception- some 1968 and later Olds 400/455's were produced with forged steel crankshafts. These rare cranks can be readily spotted by the "J" shaped notch in the OD of the rear flange; cast iron cranks have a "C" shaped notch.

All 1965 thru 1969 Olds 400's were painted bronze ( not gold ).

Engine Casting Number Deciphering

This chart will help you decipher what engine type your have in your Cutlass. While the data is somewhat inconclusive, it provides an overall point of reference for engine decoding. If you have information to fill in the gaps or see an error, please contact me.

In order to figure out what block you have in your car, you must locate the Casting Number. This can be found at the front of the engine on a flat surface behind the timing chain area. ( See picture at top of page) Look to the right (if facing the fan) of the oil filler tube and you will see the stamping on the block. This number should match one of those below. Remember, big blocks are identified by a letter for the ID Code, while small blocks carry a number.

Big Block reference chart:

Casting NumberID CodeCIDYear(s) ProducedNotes

381917A4251965B Bodies (big cars) only

386525Red A 425

389298Bronze B4001965 One year only 442 motor. The lifter cam angle bank was 45 degrees

and changed to 39 degrees in 1966

390925Bronze E4001966 - 1967442 Engine

389244D4251966 - 1967Big car engine. Toronado is different internally.

390925E4001966 - 1967 Heads were changed to a 39% bank from the 1965 45% bank.

396021F4551968 - 1972Most common big block. Two types of "F" letters: stick type, and one with two vertical hangers and a base.

396021Fa 4551972 - 1976Very common casting

396026G 4001968 - 1969442 and Vista Cruiser

231788L4551976 Motorhomes (1973 - 1978) maybe marine use also.

Small Block Reference chart:

Casting NumberID CodeCIDYear(s) ProducedNotes

38191713301964

38191723301965

39555823501968 - 1970

3 330

395558 3501973 - 1974

2A 2601976 - 1981Solid main webs for 2A's only? At least for '76

557751 2B 26019?? - 1981Windowed main webs for 2B's only?

5572654A4031977Solid main webs possibly

5539904A4031977Solid main webs possibly

5549904A4031977Solid main webs possibly

5572654B4031977 - 1979Windowed main webs always.

D3350Diesel

Early 400

Built 1965 - 1967.

Late 400

Built 1968 - 1969.

The short stroke 1965-67 400s were great engines, but in 68-69 Olds attempted to reduce emissions by using a reduced bore to minimize combustion chamber quench area and thus lower unburned hydrocarbons (emissions controls actually started in 1968 on 49-state cars). Note that this decision to go with a smaller bore was also due in no small part to the desire to use a common crankshaft with the new 455 in 1968 as well. The result is a terribly undersquare motor (3.870 bore x 4.125 stroke) which won't rev very well. This is the worst bore-to-stroke ratio of any American V8 from the modern era.

One limiting factor to your buildup will be the small bore size of your later 400, which can shroud larger valves. One great way to gain yourself some horsepower is to move up to a 455 shortblock with your stock "C" heads; more cubic inches, and the large valves will breathe even better.

The story on the change from the early 400 to the 68-69 400 was due to design changes to start limiting emissions and with the longer stroke they picked up more torque which lead to more power at lower rpm. Thus their early attempt to reduce gas consumption and increase mileage with lower emission. Plus the redesign of the internals which now shared the same crank and rods as the 455's.

I recall reading that the undersquare design of the 400 and 455 in 1968 was intended to reduce the quench area in the combustion chamber to reduce emissions. Apparently, the walls of the combustion chamber are cooler than the rest (makes sense) and fuel can condense out there and lead to incomplete burning and thus higher HC and CO emissions. By making the bore smaller, the surface area of the combustion chamber is, by definition, reduced.

Of course, while that was the published rationale, I suspect that this decision had more to do with commonality of the expensive crank forging between the 400 and 455 than anything else. Since Olds likely expected to sell many more 455s than 400s, redesigning the 400 to use the 455 crank and rods probably made a lot of financial sense.

[ Thanks to Rob Thomas, Bob Barry, Joe Padavano for this information ]

Rev Potential, Limit

The early 400 engines rev higher than any other big block. They will rev higher than a 425. Got a little less piston mass. These things will turn almost 7000 RPM.

[ Thanks to Jim Chermack for this information ]

BRO's Oldsmobile Julian Date Calender (PERPETUAL)
Day	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec	Day
1	001	032	060	091	121	152	182	213	244	274	305	335	1
2	002	033	061	092	122	153	183	214	245	275	306	336	2
3	003	034	062	093	123	154	184	215	246	276	307	337	3
4	004	035	063	094	124	155	185	216	247	277	308	338	4
5	005	036	064	095	125	156	186	217	248	278	309	339	5
6	006	037	065	096	126	157	187	218	249	279	310	340	6
7	007	038	066	097	127	158	188	219	250	280	311	341	7
8	008	039	067	098	128	159	189	220	251	281	312	342	8
9	009	040	068	099	129	160	190	221	252	282	313	343	9
10	010	041	069	100	130	161	191	222	253	283	314	344	10
11	011	042	070	101	131	162	192	223	254	284	315	345	11
12	012	043	071	102	132	163	193	224	255	285	316	346	12
13	013	044	072	103	133	164	194	225	256	286	317	347	13
14	014	045	073	104	134	165	195	226	257	287	318	348	14
15	015	046	074	105	135	166	196	227	258	288	319	349	15
16	016	047	075	106	136	167	197	228	259	289	320	350	16
17	017	048	076	107	137	168	198	229	260	290	321	351	17
18	018	049	077	108	138	169	199	230	261	291	322	352	18
19	019	050	078	109	139	170	200	231	262	292	323	353	19
20	020	051	079	110	140	171	201	232	263	293	324	354	20
21	021	052	080	111	141	172	202	233	264	294	325	355	21
22	022	053	081	112	142	173	203	234	265	295	326	356	22
23	023	054	082	113	143	174	204	235	266	296	327	357	23
24	024	055	083	114	144	175	205	236	267	297	328	358	24
25	025	056	084	115	145	176	206	237	268	298	329	359	25
26	026	057	085	116	146	177	207	238	269	299	330	360	26
27	027	058	086	117	147	178	208	239	270	300	331	361	27
28	028	059	087	118	148	179	209	240	271	301	332	362	28
29	029		088	119	149	180	210	241	272	302	333	363	29
30	030		089	120	150	181	211	242	273	303	334	364	30
31	031		090		151		212	243		304		365	31

BRO's Oldsmobile Julian Date Calender
(FOR LEAP YEARS ONLY)
Day Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Day
1 001 032 061 092 122 153 183 214 245 275 306 336 1
2 002 033 062 093 123 154 184 215 246 276 307 337 2
3 003 034 063 094 124 155 185 216 247 277 308 338 3
4 004 035 064 095 125 156 186 217 248 278 309 339 4
5 005 036 065 096 126 157 187 218 249 279 310 340 5
6 006 037 066 097 127 158 188 219 250 280 311 341 6
7 007 038 067 098 128 159 189 220 251 281 312 342 7
8 008 039 068 099 129 160 190 221 252 282 313 343 8
9 009 040 069 100 130 161 191 222 253 283 314 344 9
10 010 041 070 101 131 162 192 223 254 284 315 345 10
11 011 042 071 102 132 163 193 224 255 285 316 346 11
12 012 043 072 103 133 164 194 225 256 286 317 347 12
13 013 044 073 104 134 165 195 226 257 287 318 348 13
14 014 045 074 105 135 166 196 227 258 288 319 349 14
15 015 046 075 106 136 167 197 228 259 289 320 350 15
16 016 047 076 107 137 168 198 229 260 290 321 351 16
17 017 048 077 108 138 169 199 230 261 291 322 352 17
18 018 049 078 109 139 170 200 231 262 292 323 353 18
19 019 050 079 110 140 171 201 232 263 293 324 354 19
20 020 051 080 111 141 172 202 233 264 294 325 355 20
21 021 052 081 112 142 173 203 234 265 295 326 356 21
22 022 053 082 113 143 174 204 235 266 296 327 357 22
23 023 054 083 114 144 175 205 236 267 297 328 358 23
24 024 055 084 115 145 176 206 237 268 298 329 359 24
25 025 056 085 116 146 177 207 238 269 299 330 360 25
26 026 057 086 117 147 178 208 239 270 300 331 361 26
27 027 058 087 118 148 179 209 240 271 301 332 362 27
28 028 059 088 119 149 180 210 241 272 302 333 363 28
29 029 060 089 120 150 181 211 242 273 303 334 364 29
30 030 090 121 151 182 212 243 274 304 335 365 30
31 031 091 152 213 244 305 366 31

Motor Mounts & Mounting Pad Selections:

The question of which motor mounts to use when replacing an A-Body (F-85, Cutlass, Cutlass S, Cutlass Supreme, 442) small block with a big block is one that's asked all the time.

All Olds engines (big and small block) have the motor mount bosses in the same location in relation to the crank centerline. The only difference is the deck height. The year of the block (or the displacement for that matter) has absolutely NO effect on the type of motor mount to use. The only thing that matters is the matching frame mount. You must use the motor mount that matches the frame mount in the car.

If it was orignally a small block car and you do not intend to change the frame mounts, get small block motor mounts. These will bolt to the big block and will allow the engine to sit in the exact same location relative to the frame as it would have in a factory installation. Alternatively you could use matching big block motor and frame mounts, but for all this extra expense and effort the engine will still be sitting in the same location.

Small block engine mounts with small block frame mounts - OK

Big block engine mounts with big block frame mounts - OK

Small block engine mounts with big block frame mounts - the engine will be 1-2" too low

Big block engine mounts with small block frame mounts - the engine will be 1-2" too high

Note: The big block is about an inch taller than the small block when measuring from the crank centerline to the carb flange, so even if you use matching mounts, the air cleaner and valve covers will be higher in the engine compartment. The crank centerline, fan, and flywheel will all be in the same location as they were with the small block.

"The only thing you need to remember is that the rubber motor mounts and the metal frame mounts need to match. Nothing else matters."

The 64-69 small block and 65-68 big block motor mounts are identical. The 1969 400 mounts (and 455 for the 69 H/O) were changed to the taller design used on the 69-72 cars. The small block mounts were changed in 1970. Sealed Power 270-2261 - 1964-69 all V8 exc. 69 w/400

History

1964 - 1968 small and big block motor mounts 270-2261

1969 - 1972 small block motor mounts 270-2261

1969 - 1972 big block motor mounts 270-2328

1973 - up small and big block motor mounts 270-2380

The problem started in 1969. The original motor mounts used on the earlier cars were simply two pieces of metal with rubber molded in between - there was no interlocking feature. GM went through a massive recall in the 60s to repair broken motor mounts of this design. As a result, the big block cars, starting in 1969, got the interlocking design. Unfortunately, this design required the motor mount to be taller, so the frame mount was changed to move the cross bolt (the bolt that attaches the motor mount to the frame mount) further down on the frame mount. The 64-68 (and 69 small block) frame mounts have the cross bolt hole about 1 1/2" down from the centerline of the two top bolts that attach the frame mount to the crossmember. On the 69-72 big block mounts, this dimension is about 2 1/4". The rubber motor mounts are correspondingly different (the 69-72 big block motor mount is about 1" taller than the 64-68 V8 (and 69 small block) mounts.

In 1970, Olds redesigned the small block mounts to also incorporate the interlocking feature, but did this in a way that did not require the cross bolt to be moved. Thus the 70-72 small block frame mounts still use the 1 1/2" dimension. There is, however, a difference between the 70-72 small block mounts and the 64-68 V8 (and 69 small block) frame mounts. The raised pad is smaller and biased towards the top of the mount. Thus, I do not think it is possible to use the 70-72 small block motor mounts on the 64-68 frame pads. On the other hand, it probably _is_ possible to use the 68-68 V8 (and 69 small block) mounts on the 70-72 frame mounts.

Finally, starting in 73 Olds realized that there was no reason to maintain two different motor mount designs and went back to using a common motor and frame mount design on both big and small blocks.

And one more word of advice. Don't rely on any catalog, other than the factory parts catalog, to tell you what motor mounts fit where. As I noted in a prior post, the Sealed Power catalog is flat wrong.

Identifying Frame Pads:

You can check by measuring from the center of the two top bolts that hold the mount to the frame to the center of the cross bolt that attaches the frame mount to the motor mount. The big block frame mounts will measure about 2 1/4", while small block mounts will measure about 1 1/2". Whichever ones you have (big or small block), get the motor mounts to match.

When bolting the motor mounts to the block, there are three tapped holes on each side. The front two are for full size cars, the back two for F-85's.

The 1970-earlier B/C body cars use a motor mount that is completely different from the A-body mounts. The rubber mount has a threaded stud that fits into a hole in the frame. A nut is installed from the underside. One other wrinkle is that some B/C body cars DO use a 1" shim under one motor mount (see notes on the Cutlass offset engine myth.) If the shim is there on the 350, use it in the same place on the 455. Also, note that B/C body motor mounts bolt to the forward two of the three bosses on each side of the block. The A-body cars use the rear two bosses.

Q) Are the 69 onward small block motor and frame mounts exactly the same as the early "one size fits all V8's" units.

A) The answer unfortunately is no. The 69-up small block mounts are not the same as the 68-down universal mounts. The net combination of matched motor and frame mounts for a specific year is always the same, but the individual parts may be different from year-to-year.

Q) What is the earliest year motor and frame mounts that will put a V8 into an A-Body?

A) 1964 330 motor and frame mounts used as a matched set will install any 64-up (except, of course, the 394) Olds V8 in a 64 A-body. Ditto for 65, 66, etc.

Q) Are there any better quality mounts or mounts to avoid?

A) General concensus is that the G.M. rubber mounts (made in the U.S.A.) are the best rubber ones. Also, for reference, the Mondello SM300 mounts appear to be solid versions of the Sealed Power 270-2261 mounts and SM400's appear to be the solid version of the 270-2328.