by Frank Swygert – last updated 11-29-2025
AMC Engines – 1954-1991
There is a brief introduction followed by links (in red text) to the various AMC engines. More will be added as time allows!
Introduction
Contrary to popular belief (and most AMC enthusiasts know this!), AMC manufactured their own engines — with a few exceptions. Many people seem to believe that due to similar displacements, and some of the accessories used, that AMC purchased engines. The 232 six was a Chevy 230, the 327 was a Chevy 327, the 390 was a Ford, and the 290 was also a Ford 289. Those are the most commonly mentioned. In the case of the 290 and 390 it didn’t help that they often had Autolite carburetors and Motorcraft ignition and charging systems (both Ford brands) and up through 1971 Borg Warner automatic transmissions — which were very similar to the Ford FMX (due to Ford licensing the Borg Warner design back in the mid 1950s).
It doesn’t help that AMC actually did use a few outsourced engines, all as stop-gaps until they could get their own designs into production. I’ve listed the few non-AMC engines used by AMC in passenger cars below.
1. 1955-56 Packard V-8 (320 in 55, 352 in 56 – 5.2L/5.8L). George Mason, AMC’s CEO from 1937 until his unexpected death in 1954, championed an eventual merger of AMC with the Studebaker-Packard corporation. He saw early on the the last few independent auto makers just didn’t have the financial power to compete with GM, Ford, and Chrysler. That led to the Nash-Hudson merger, and Studebaker-Packard merger. Others, such as Kaiser-Frazer, simply went out of business by the late 50s, unable to effectively compete. As part of this eventual merger strategy AMC and S-P had a hand-shake agreement to share some parts and manufacturing. AMC bought Packard V-8s with Twin Ultramatic transmissions (they were required to get the transmission with the engines) for use in the Nash Ambassador and Hudson Hornet. Packard was to buy some parts from AMC, but S-P CEO James Nance apparently felt that his agreement was with Mason, not AMC, as the agreement fell apart after Mason’s death. Romney and Nance reportedly didn’t get along that well, while Nance had great respect for Mason. Packard rejected all bids on parts from AMC as too expensive — there is no known information to back the claim up (or deny it). This incensed Romney, and he ordered his engineering department to come up with an in-house V-8, as it was sorely needed to compete in the mid 50s and later. Romney had also informed Packard that the engine contract would be terminated at the end, to which Packard responded that the contract would be terminated earlier, specifically because they needed all their in-house production for their own cars.
2. 1977-79 Audi/VW 121 (2.0L) I-4. AMC needed a four cylinder engine to compete in the late 70s and early 80s. They had been doing well with their 232 six for economy conscious buyers (the smaller 199 was discontinued after 1970), but the gasoline shortages of 1973 had buyers looking harder at smaller engines. They wanted it fast, so decided that buying a design form someone else would speed up the process. They ended up purchasing the Audi/VW EA831 design. It was small, but developed good power due to it being a modern OHC design. It was actually used mostly in VW LT trucks (about 1 ton to 3 ton load capacity) and Audi 100 cars. Many mistakenly believe this was the Porsche 924 engine, but it’s not. Porsche used a variant in their 924, but just the long block is VW/Audi — Porsche redesigned the cylinder head and added fuel injection for better performance (95-110 hp). AMC purchased an assembly plant specifically to produce these engines. Initially they were assembled in the US from major castings (block, head, crankshaft, etc.) imported from Germany with some US made components (mostly accessories, covers, brackets, water pumps, etc.). The goal was for AMC to purchase the tooling and move complete production over to the US, but demand never reached a high enough level. The little 80 hp engine (only 70-74 HP in the VW LT) just didn’t have enough power when used in the Gremlin and especially the heavier Hornet that American drivers were accustomed to. The engine was a high revver — 80 hp was achieved at 5,000 rpm and peak torque of 105 ft/lb at 2,800 rpm. The 232 six used more fuel but produced 100 hp @ 3600 rpm and 185 ft/lb torque at a comparatively low 1800 rpm. The 2.0L was adequate in a manual transmission Gremlin or Spirit, but woefully lacking for American driving when in the heavier Hornet/Concord or when mated to an automatic in the smaller cars, especially if loaded down with options like AC. AMCs plan had been to use the engine “for now” in their existing cars but they knew a newer, smaller car was needed. Unfortunately they couldn’t get the financing to develop a car to suit the engine, not after the costs of developing the Pacer and Matador Coupe took their toll.
3. 1979-83 GM/Pontiac “Iron Duke” 150 (2.5L) I-4. With the failure of the Audi/VW 2.0L AMC still needed a four! They turned to GM and were able to purchase the 2.5L Iron Duke. This replaced the 2.0L in AMC cars and was also used in Jeep CJs (the 2.0L had been used only in 2WD mail Jeeps). This older GM design used the small block Chevy V-8 bolt pattern. AMC had Chrysler 904 transmissions cast with the SBC pattern to use with the engine rather than buying GM transmissions.
That’s it for passenger cars… only THREE outsourced engines.
Jeeps used a few more:
1. 1970-71 Kaiser/Buick 225 (3.7L) V-6. This wasn’t really outsourced. AMC got the design when it bought Kaiser Jeep in 1970. Kaiser had purchased the design and manufacturing rights when Buick stopped making it (Kaiser had been buying them from Buick) after the 1967 model year. AMC just used up existing stocks of the engine in the CJ while they adapted the CJ for the AMC 232 six. So in a way it’s really an AMC engine… at least when AMC was using it.
2. 1984-86 GM 171 (2.8L) V-6. When the new XJ Cherokee came out in 1984 it received either the new AMC 2.5L four or an optional GM sourced 2.8L V-6. According to a former Jeep engineer there were several engineers who simply didn’t want AMC to put their by then dated carbureted straight six in the new vehicle, so they specifically designed the engine bay to be too short for it. The small V-6 was the only one GM was willing to sell to AMC — the 3.8L (229) or 4.3L (262) SBC derived models would have been better choices, but their width would have made them a tighter fit (Novak sells mounts to SBC and LS swap an XJ, so the SBC/big V-6 will fit). The small V-6 was hardly worth the effort — it only made 5 hp and about 10 ft/lbs more than the standard AMC four. Still, AMC felt that a six cylinder option was necessary. Then VAM showed AMC an XJ prototype in 1982 with the VAM built AMC I-6 in it anyway (firewall was modified), which led to the development of the 4.0L I-6 and a modification to the firewall to accommodate it.
3. 1984-86 Renault J8S 126 (2.1 L) turbo-diesel. This little diesel engine was optional in the XJ line. It was only used with manual transmissions, a standard four speed or optional five speed. It produced 85 hp @3,750 rpm, 132 ft/lb@2,750 rpm. There was virtually no turbo lag, exceptional for the time. Few found buyers in the US and it’s relatively rare to find one today.
Only THREE more when you include Jeep only applications
AMC Manufactured Engines
The 195.6 OHV I-6, 1956-1965 (iron block)
This section was written mostly by Tom Jennings and based on the extensive modification work he did on this engine in the early 2000s. The information will mostly apply to stock OHV engines and much of it is also applicable to the L-head (flat-head) model.
1961-64 195.6 OHV I-6 (aluminum block)
This was a short lived engine that just didn’t pan out! It shared many components with the cast iron block version. Today iron blocks with aluminum heads are common, an aluminum block with an iron head seems strange! The block was die-cast using a permanent steel mold which saved a lot of manufacturing costs and time as well as some weight. A head can’t be die-cast, so a lot of the savings just isn’t there. In the early 60s aluminum actually costs more than iron.
1956-1966 Gen1 V-8 (250/287/327)
The first AMC designed and produced V-8 engines.
Barney Navarro Indy Turbo Six
In 1967 a car powered by an AMC six was entered at the Indianapolis 500. It didn’t qualify, more due to drivers and suspension issues than the engine. Several attempts were made up to 1972.