AMC V8 engine


designed and manufactured two distinct V8 engine designs. Their first V8 engine design was made from 1956 through 1967. The second design debuted in 1966 and was made through 1991. Chrysler kept the last design in production until 1991 for the Jeep Grand Wagoneer.

American Motors Corporation "Rambler V8" (1956–1967)

This was AMC's first V8 engine designed and manufactured from 1956 to 1967.
American Motors' president, George W. Mason, negotiated a verbal agreement with Packard that the two companies would supply parts for each other when practical. This was a prelude to a possible merger of the two companies at a later date, but that never occurred. With the industry-wide acceptance of V8 engine designs after World War II, AMC started buying Packard V8s in 1954 for the 1955 Nash Ambassador and Hudson Hornet. These were supplied with Packard "Ultramatic" automatic transmissions - exclusively. Packard sent AMC some parts bids, but these were rejected as too expensive. George W. Romney, AMC's new leader, decided against further relationships with Packard shortly after entering the position of CEO in October 1954 after Mason's sudden death.
Romney ordered development of an in-house V8 as soon as possible. The program was under the direction of Meade F. Moore, Vice-President of Automotive Research and Engineering, along with teams in AMC's Kenosha and Detroit Engineering Departments. They were able to get the all new V8 into production in less than 18 months.
The new V8 engines, available in different displacements were of the same basic design. All these engines share common external dimensions, light weight - about - forged crankshaft and rods, as well as most other parts. The stroke for all Gen-1 V8s is. Engine displacement was a factor of the bore: the has a bore, , and the a bore. The bore size on the 327 is cast on the top of the block near the back of the right bank cylinder head and is denoted by a '4'. The 250 and [|287] engines do not have the bore size cast into the block. The block features a deep skirt where the casting extends below the crankshaft centerline, forming a very rigid crankcase gallery. The oil system feeds a central gallery to the cam and crankshaft first from front to rear, and then dividing at the front to feed the two lifter galleries from front to rear. From the rear of the two lifter galleries oil is then supplied up to the two rocker arm shafts which serve as galleries to lubricate the valvetrain. The fore and aft direction changes are designed to eliminate stale oil areas which tend to form sludge deposits.

250

American Motors' first V8 in-house engine, the 250, was used in AMC automobiles from 1956 through 1961. It was a modern OHV/pushrod engine design and made its debut in the Nash Ambassador and Hudson Hornet "Specials" of 1956. These cars had the top-of-the-line model trim, but were built on the shorter wheelbase models. The 250 uses solid lifters and came in two- and four-barrel carburetor varieties.
The 250 V8 was optional in the 1957 Rambler. All 1958-60 V8 Ramblers were called "Rebels" and designated as a different series. It is easy to confuse the 1957 Rambler V8 and the 1958-'60 Rebel line with the special 1957 Rambler Rebel, a limited edition muscle car. In 1961, The Rambler Six was renamed the "Rambler Classic" to avoid model confusion in the Rambler line-up. A V8 engine then became an option in the Classic instead of a separate model.

287

In mid-model year 1963, AMC introduced a V8. When the 250 was dropped in 1961, there was no V8 option for Rambler models other than the top of the line Ambassador, which was only available with the 327. Dealers complained, so the 287 was introduced as an option for the "mid-size" Rambler. Like the 327, it uses hydraulic valve lifters. Only two-barrel models were produced, there were no four-barrel options from the factory for the 287 as this was the economy model V8. The 287 engine was produced through the 1966 model year.

327

The AMC 327 is similar to the 287, but displaces due to the bore increase to. Unlike the 250, the 327 was produced with hydraulic valve lifters. Contrary to some myths, the AMC V8 was not built by Chevrolet, whose own 327 V8 later became better known. The AMC 327 was introduced five years before the Chevrolet 327 engine was manufactured.
The AMC 327 engine debuted in a special edition Rambler Rebel, of which 1,500 were made. They were an early American muscle car. All Rebels had silver paint with a gold-anodized "spear" on each side. The 327 was not available in any other Rambler models in 1957 other than the special edition Rebel. The Rebel's engine differs from the 327s installed in the 1957 Nash Ambassador and Hudson Hornet models in that it uses mechanical valve lifters and a higher compression ratio. Since both engines were rated at, it is probable that the Rebel's was underrated.
The Nash Ambassador and Hudson Hornet "Special" models were dropped after 1957, replaced by the 1958 Rambler Rebel with the 250 V8. The Rebel was a Rambler with a V-8. The Rebel name was added to differentiate the standard six-cylinder Rambler from the V-8 model. The big Nash and Hudson cars were also dropped after 1957, replaced by the 1958 "Ambassador by Rambler" — a stretched Rebel with the 327 V8 instead of the 250. The 327 was exclusive to the Ambassador line and could not be ordered in a Rebel through 1964. For 1965 and 1966 the 287 and 327 were both available in the Classic and Ambassador.
The 327 was sold to Kaiser-Jeep from 1965 to 1967 for use in the Jeep Wagoneer SUV and Gladiator pick-up truck. Jeep named it the "Vigilante" V8. Two barrel carburation was standard on these Jeep models, but a four barrel high-compression version was available in the high optioned Super Wagoneer from 1966 to 1968. Kaiser-Jeep switched to the Buick 350 in 1967 after AMC discontinued the 327. The Buick V8 engine option continued through 1971 after which Jeeps returned to AMC V8 engines, American Motors having purchased Jeep from Kaiser in 1970.
There were low- and high-compression versions of the 327 starting in 1960. Prior to 1960 all 327s were high compression. All low compression models used a two-barrel carburetor and all high-compression models received a four-barrel carb. Low-compression is 8.7:1, high 9.7:1, effected by a difference in pistons.
The 327 was also offered as a marine engine as the "Fireball" by Gray Marine Motor Company.

Electronic fuel injection

The AMC 327 was to be the first commercial electronic fuel injected "Electrojector" production engine. Press reports about the Bendix-developed system in December 1956 were followed in March 1957 by an AMC price bulletin offering the EFI option on the Rambler Rebel for US$395, but due to supplier difficulties, fuel-injected Rebels were only available after 15 June. Teething problems with the Electrojector unit meant that only a few engineering and press cars were built, estimated to be no more than six units. At least two pre-production Rebels with EFI, however, are known to have been built. One was sent to Daytona Beach, Florida for "Speed Week". It was the second fastest car on the beach, bested only by a 1957 Chevrolet Corvette with mechanical fuel injection, and only by a couple tenths of a second.
The EFI 327 was rated at and the regular four-barrel carbureted model at. The EFI system in the Rebel was a far more-advanced setup than the mechanical types then appearing on the market and the engines ran fine in warm weather, but suffered hard starting in cooler temperatures. All the EFI cars were reportedly converted to four-barrel carbs before being sold; none are known to have existed outside the engineering department at AMC.
The main problem was that early electronics were not fast enough for "on the fly" engine controls. This setup was utilised by Chrysler for the 1958 model year on its Dodge, Chrysler, Plymouth, and DeSoto carlines. It too failed, having the same problems.
Bendix licensed patents based on their 1950s design to Bosch, who perfected it as the basis for their D-Jetronic, et seq. injections system, first used in 1967.

Marine application

The 250 and 327 were also offered as a marine engine known as the "Fireball" by Gray Marine Motor Company starting in 1958. Gray started offering the 250 in 1959. The 250 was offered in 135, 160, 170, 175, 178 and 185 horsepower versions. The 327 was made in 188, 215, 220, 225 and 238 horsepower levels. Gray used the 250 through 1966. The 327 was used as a 220 hp model in 1967, the last year an AMC V-8 was used.

Gen-2 AMC short-deck V8 (1966–1970)

The new-generation AMC V8 was first introduced in 1966. It is sometimes referred to as the "Gen-2" AMC V8. The first version was the completely new Typhoon V8 introduced in a special mid-1966 model year "Rogue" hardtop. Available in two-barrel carburetor version or producing with a four-barrel carburetor and high compression, the new engines utilized "thin-wall" casting technology and weighed only.
All three engine sizes -,, and - share the same basic block design—the different displacements are achieved through various bore and stroke combinations. All blocks share the same external measurements and thus can be swapped easily.
Bore center measurement was kept the same as the Gen-1 V8 at so that boring equipment could be reused. Other than that, this engine is vastly different from the Gen-1 model. The Gen-1 engine is physically the size of a big-block Ford or GM engine, and is sometimes called a "big-block". The Gen-2 is closer to the physical size of U.S. made small-block V8s except for the bore centers, which are the same as some big-block engines. The only parts shared between the 1966-67 Rambler V8 and 1966-91 AMV8 are the lower cam timing sprocket and the timing chain.
The AMC V8 was not built by Ford or anyone else although it bears an uncanny resemblance to the later Buick V8 engines. It shares the same design employing a timing gear case that mounts both distributor and oil pump. It also shares the same oiling scheme employing a single passage to feed both cam and crank from the right lifter bank by tangentially intersecting the cam bore instead of two drilled passages, one from the cam to crank and another from the crank to the right lifter bank. Some electrical parts were shared with Fords, and some models used Motorcraft carburetors, but the balance of the engine design is unique.
The Gen-2 AMC V8 was first introduced at in 1966. It was used exclusively in the Rambler American model the first year. The came out in 1967 and the AMX arrived in mid-1968. These engine blocks were unchanged through the 1969 model year.
The head used during this time was the so-called "rectangle port", named after its exhaust port shape. The 290 heads use smaller valves, intake and exhaust, in order to prevent problems with the small bore. The 343 and the AMX 390 use the same larger valve heads, intake and exhaust.

Indy 209

From 1976 to 1979, Jerry Grant "drove the most powerful car ever to appear in Indy car racing" - a turbocharged two-valve, AMC Gen-2 block V8 engine producing in his Eagle 74 chassis. The car was fast on the straightways, but the engine's weight made corners more difficult to handle. The engine utilized a bore and a flat plane stroke crankshaft.

290

The base produces with a two-barrel or four-barrel carburetor, respectively. It was built from the mid-1966 model year through the 1969 model year. It has a bore and stroke of. Only 623 cars were built in 1966 with the 290 engine. These engines were available in special Rambler American two-door Rogue models. The newly powered Rogue was available with either a three-speed automatic or a floor mounted four-speed manual transmission, and made the car "suitable for the Stoplight Grand Prix."

343

The has a bore and stroke of. The basic 343/2V produced and was built from 1967 through 1969. Output for the optional four-barrel carburetor version is and produces of torque. This version has a 10.2:1 compression ratio.

AMX 390

In addition to the largest bore and stroke, the AMX motor also received heavier main bearing support webbing and a forged steel crankshaft and connecting rods. Forged cranks and rods were used for their known strength—there was inadequate time for testing cast parts for durability without delaying AMC's introduction schedule. Once forging dies were made it was not cost effective to test cast parts due to the relatively low number of engines produced. The use of these stronger components was also continued with the production of 401 engines. This is an advantage of these AMC engines when used in heavy-duty and high-performance applications because they have no problems with their rods breaking; unlike other domestic automakers' large displacement small block engines. The Gen-2 AMX 390 produces and was built in 1968 and 1969. Bore and the stroke is. Maximum factory recommended overbore is only, although they are commonly bored. In 1970, AMC changed the head to the "dog-leg" exhaust port design.

Gen-3 AMC tall-deck (1970–1991)

In 1970, all three blocks grew in deck height and gained a new head design. These changes made this the third generation of AMC V8, hence it is sometimes referred to as the "Gen-3" AMC V8. The stroke and deck height on the 290 and 343 was increased by on both engines, becoming the and, respectively. The 1970 AMX 390 remained at the same displacement by using a special rod and piston for this year only. It is believed that AMC kept the 390 this last year due to the reputation it had garnered in the two seater AMX, which was discontinued after 1970. In 1971 the 390 was also stroked by to become the 401 engine.
The other change in 1970 was the switch to the "dog-leg" heads. These heads flow 20% better on the exhaust side than the 1966-1969 rectangular port heads and are thus the best for performance. There are two reasons for the flow increase: the area of the port is larger, due to the dog leg and the shape of the port floor was changed from a concave to a convex curve. The concave floor tended to bend the exhaust flow upwards which caused turbulence when the flow was forced to go down into the exhaust manifolds. By switching to a convex floor the curvature of the flow starts in the head and proceeds much more smoothly into the exhaust manifold resulting in less turbulence and better flow.
The center two intake bolts on each head were relocated to prevent accidental mix-ups of Gen-2 and Gen-3 intakes. The intakes can be interchanged by slotting the bolt holes, but the added deck height of the GEN-3 engine means that sealing and port match will be compromised. Gen-3 intakes can be machined to fit Gen-2 engines by surface grinding the intake flanges and slotting the center holes.
There is a persistent myth about 1970-mid 1971 319 and 291 AMC heads. These heads have the dog-leg exhaust ports and 50-52 cc combustion chambers. They are commonly identified by the first three or last three digits of the casting number. There was a U.S. auto industry-wide shift to lower compression ratios in mid 1971, so AMC increased combustion chamber size to 58-59 cc. The first three digits of the casting number on the large chamber heads are 321, 322, or 323 depending on year. The only difference between small and large chamber Gen-3 heads is the combustion chamber size.
The advertised power drop from 1971 to 1972 is not due to any engine change, but to in the way the automobile industry adopted SAE power rating method. The 1971 and 1972 engines produce the same power. The 1971 and earlier versions were rated using "gross" horsepower, which is with the engines operating with no accessories or drive belts, air filters, nor any exhaust system restrictions. The change to the more realistic "net" horsepower ratings for 1972 and later required the engine to be driving all stock factory accessories and to use the factory air filter system and a simulated factory exhaust. Power is measured at the flywheel for both systems. For example, even with the modifications to more reduce emissions and increase efficiency, AMC's engine was among the strongest factory-spec engines available in an American car in 1971, with more horsepower than Pontiac's standard and Chevrolet's that powered the Corvette.

304

The 304 has a displacement of which produced in 1970-71 and was built starting in 1970. Later models produced less power from the factory, going down yearly. 1972-75 models were rated at . It was rated at in 1978, and in 1979, the last year it was installed in passenger cars, and in 1980–81, the last years it was used in Jeep vehicles. The International Harvester Corporation SV "Comanche" V8 engines are sometimes mistaken for the AMC 304, however the IHC V8 engine family has no relation to the AMC V8 and was in fact first produced in 1959,11 years prior to the AMC designed 304. The similarity in displacement is purely a coincidence.

360

The AMC 360 has a displacement of. The 2-barrel produced to in 1970 to early 1971 while the 4-barrel produced to, to from mid-1971 to 1975, to in 1976, in 1977, and from 1978 to 1991.
This engine was used in the 1970 AMX as the base engine and also in the 1970 Rebel, 1971-1978 Matador, Jeep J-series trucks 1970–1987, Wagoneer models from 1972 to 1984, Cherokee from 1974 to 1983, as well as in the full-sized Grand Wagoneer from 1984 to 1991 - becoming the last carbureted engine used in an American-built vehicle. The 360 V8 was also installed in the Bricklin SV-1 sports car for 1974 model year.
The 360 was the last AMC V8 to be manufactured. It continued to be produced after Chrysler bought American Motors in 1987 as the standard engine in the Jeep Grand Wagoneer through 1991, with the only modification being the "360" casting replaced with "5.9L" on the side of the block.

390

The AMC V8 produced and of torque in all except the Rebel Machine. This muscle car engine was rated at and of torque due to a different intake. Production only lasted one year before it was stroked to become the. Like the Gen-2, the maximum factory recommended overbore is only, though they are commonly bored.

401

The produced gross in 1971 and net from 1972 to 1975. In 1976 it was rated at. Like the 390, the 401's crankshaft and connecting rods are forged steel. Like the 390, factory recommended overbore is only, but commonly bored by. It was last produced in 1979.
The 401 was available in the Javelin, Matador, and Ambassador car lines and in Jeeps from its introduction in 1971 through 1974. In 1975 and 1976, emission controls, insurance rates, and high gasoline prices meant the 401 was available on the large Matador model, and then only for police department orders. Buyers of full-sized Jeeps could order a 401 until 1979. This engine was also supplied to International Harvester for use as an optional engine in International's Light Line pickup trucks and Travelalls from late 1973 through 1974 where it was designated 'V-400' to differentiate it from IHC's own V/LV series 401.

"Service replacement" blocks

There was also a "Service Replacement" block made as a modified GEN-3 design. This is a 401 casting without the displacement cast into the side and with a 360 bore and thicker deck. In theory this single block could be built as any 343-401 GEN-2 or GEN-3 engine. A dealer could stock one or two blocks to use for warranty replacement.
The main bearing web area was thicker in the 390, 401 and SR blocks, thick enough that two additional bearing cap bolt holes could be drilled and tapped for an aftermarket four bolt main cap, providing a stronger bottom end. AMC never built a factory four bolt main block, they sold aftermarket four bolt main caps through their Group 19 performance parts program.
The SR block also sold as a heavy duty racing block. It appeared in 1970 in time for the 1971 Trans-Am racing season, and was used in the factory Trans-Am backed cars prepared by TRACO for Penske Racing, with Mark Donohue the primary driver. Since it was a standard factory part it did not have to be homologated under T/A rules, and was not used in the 2501 "Mark Donohue" Javelins built to homologate the "duck tail" spoiler. Those received standard 360 or 390 engines, buyers choice.

AMC V8 engine summary

YearDisplac.-Carb.Power
hp 		Torque
lb·ft 		Comp.
ratio		Bore
in 		Stroke
in
1966287-2B198 @ 4700280 @ 26008.7:13.75 3.25
1966327-2B250 @ 4700340 @ 26008.7:14 3.25
1966327-4B270 @ 4700360 @ 26009.7:14 3.25
1967290-2B200 @ 4700285 @ 28008.7:13.75 3.28
1967290-4B225 @ 4800300 @ 320010.0:13.75 3.28
1967343-2B235 @ 4400345 @ 26008.7:14.08 3.28
1967343-4B280 @ 4800365 @ 300010.2:14.08 3.28
1968290-2B200 @ 4600285 @ 28009.0:13.75 3.28
1968290-4B225 @ 4700300 @ 320010.0:13.75 3.28
1968343-2B235 @ 4400345 @ 26009.0:14.08 3.28
1968343-4B280 @ 4800365 @ 300010.2:14.08 3.28
1968390-4B315 @ 4600425 @ 320010.2:14.165 3.574
1969290-2B200 @ 4600285 @ 28009.0:13.75 3.28
1969290-4B225 @ 4700300 @ 320010.0:13.75 3.28
1969343-2B235 @ 4400345 @ 26009.0:14.08 3.28
1969343-4B280 @ 4800365 @ 300010.2:14.08 3.28
1969390-4B315 @ 4600425 @ 320010.2:14.165 3.574
1969390-4B 340 @ 4800430 @ 340012.2:14.165 3.574
1970304-2B210 @ 4400305 @ 28009.0:13.75 3.44
1970360-2B245 @ 4400365 @ 26008.5:14.08 3.44
1970360-4B 290 @ 4800390 @ 300010.2:14.08 3.44
1970360-4B 295 @ 4800395 @ 300010.5:14.08 3.44
1970390-4B325 @ 5000420 @ 320010.2:14.165 3.574
1970390-4B 340 @ 5000427 @ 360010.2:14.165 3.574
1971304-2B210 @ 4400300 @ 26008.4:13.75 3.44
1971360-2B245 @ 4400365 @ 26008.5:14.08 3.44
1971360-4B 295 @ 4800395 @ 300010.5:14.08 3.44
1971360-4B 285 @ 4800385 @ 30009.5:14.08 3.44
1971401-4B 335 @ 5000435 @ 340010.2:14.165 3.68
1971401-4B 330 @ 5000430 @ 34009.5:14.165 3.68
1972304-2B150 @ 4200245 @ 25008.4:13.75 3.44
1972360-2B170 @ 4000285 @ 24008.25:14.08 3.44
1972360-4B195 @ 4400295 @ 29008.25:14.08 3.44
1972360-4B 220 @ 4400315 @ 31008.25:14.08 3.44
1972401-4B235 @ 46008.25:14.165 3.68
1972401-4B 255 @ 4600345 @ 33008.25:14.165 3.68
1973304-2B150 @ 4200245 @ 25008.4:13.75 3.44
1973360-2B170 @ 4000285 @ 24008.25:14.08 3.44
1973360-4B195 @ 4400295 @ 29008.25:14.08 3.44
1973360-4B 220 @ 4400315 @ 31008.25:14.08 3.44
1973401-4B235 @ 46008.25:14.165 3.68
1973401-4B 255 @ 4600345 @ 33008.25:14.165 3.68
1974304-2B150 @ 4200245 @ 25008.4:13.75 3.44
1974360-2B170 @ 4000285 @ 24008.25:14.08 3.44
1974360-4B195 @ 4400295 @ 29008.25:14.08 3.44
1974360-4B 220 @ 4400315 @ 31008.25:14.08 3.44
1974401-4B235 @ 46008.25:14.165 3.68
1974401-4B 255 @ 4600345 @ 33008.25:14.165 3.68
1975304-2B150 @ 4200245 @ 25008.4:13.75 3.44
1975360-2B175 @ 4000285 @ 24008.25:14.08 3.44
1975360-4B195 @ 4400295 @ 29008.25:14.08 3.44
1975360-4B 220 @ 4400315 @ 31008.25:14.08 3.44
1975401-4B255 @ 4600345 @ 33008.25:14.165 3.68
1976304-2B120 @ 3200220 @ 22008.4:13.75 3.44
1976360-2B140 @ 4000260 @ 24008.25:14.08 3.44
1976360-4B180 @ 4400280 @ 28008.25:14.08 3.44
1976401-4B215 @ 4200320 @ 28008.25:14.165 3.68
1977304-2B121 @ 3450219 @ 20008.4:13.75 3.44
1977360-2B129 @ 3700245 @ 16008.25:14.08 3.44
1977360-4B170 @ 3500280 @ 28008.25:14.08 3.44
1977401-4B195 @ 3500305 @ 28008.25:14.165 3.68
1978304-2B130 @ 3200238 @ 20008.4:13.75 3.44
1978360-2B140 @ 3350278 @ 20008.25:14.08 3.44
1978360-4B8.25:14.08 3.44
1978401-4B8.25:14.165 3.68
1979304-2B125 @ 3200220 @ 24008.4:13.75 3.44
1979360-2B245 @ 4400365 @ 26008.5:14.08 3.44
1979360-4B4.08 3.44
1979401-4B4.165 3.68
1980304-2B125 @ 3200220 @ 24008.4:13.75 3.44
1980360-2B4.08 3.44
1980360-4B4.08 3.44
1981304-2B125 @ 3200220 @ 24008.4:13.75 3.44
1981360-2B4.08 3.44
1981360-4B4.08 3.44
1982360-2B4.08 3.44
1982360-4B4.08 3.44
1991360-2B144 @ 3000280 @ 16004.08 3.44
1991------