AMC 360 Engine for Sale | Jeep V8 5.9L (1970 to 1991)

About This Engine

The AMC 360 is the longest-lived V8 engine American Motors Corporation ever built- produced continuously from 1970 through 1991, ending its automotive life as the standard engine in the last Jeep Grand Wagoneer that rolled off the line in 1991. AMC introduced the 360 in 1970 as a direct development of the 343 cubic inch engine from the 1966 to 1969 era, increasing deck height and stroke to achieve the larger displacement. Its defining characteristic was straightforward American V8 engineering executed well: high-nickel cast iron block, non-siamesed cylinder bores with water between all cylinders, 2.025-inch intake valves with dog-leg exhaust ports, and 2-bolt main caps that provided more than adequate strength for the engine’s intended operating range.

In AMC car applications- the AMX, Javelin, Hornet, and Matador- the 360 produced up to 290 hp (SAE gross) in 1970. The compression and output fell through the 1970s as emissions regulations arrived. By the late 1970s, the detuned 360 was producing as little as 125 hp. When Chrysler acquired AMC in 1987 and retuned the engine for the final Grand Wagoneer applications, output settled at 144 hp- honest and adequate for a 5,000-pound luxury SUV.

The Jeep Grand Wagoneer with the AMC 360 is the dominant application in today’s used engine market. Grand Wagoneers are having a cultural moment- original examples in good condition regularly sell for $30,000 to $80,000 or more, and the 360 is integral to the vehicle’s identity and value. A compression-tested, rear-main-checked AMC 360 with documented casting numbers is a meaningful find for any Grand Wagoneer restoration.

Signs You Need a Replacement Engine

• Oil leak at the rear main seal- the AMC 360’s most common and most chronic issue. The rope-style rear main seal is a known seep point on aged engines. We specifically inspect and report on rear main seal condition before shipping.
• Knock under load- rod or main bearing wear on high-mileage examples
• Low oil pressure at idle after warmup- main bearing wear or oil pump wear
• Oil leaks at the intake manifold and timing cover- common on aged AMC V8 engines
• Loss of compression on one or more cylinders- ring wear or scored cylinder walls
• Rough idle that varies with engine temperature- worn cam lobes on engines run on low-zinc modern oil

Known Problems With This Engine

• Rear main seal- the AMC 360’s most notorious issue: The rope-type rear main seal used by the AMC 360 is a chronic seep point on aged engines. It is not a catastrophic leak in most cases but is persistent and cosmetically objectionable. We specifically assess and report on rear main seal condition before every unit ships.
• Oiling system valley line concern on high-performance builds: At sustained high RPM (not relevant for stock Jeep operation), the AMC 360’s oil supply to the front of the valley can be insufficient. This is addressed with the ‘valley oil line’ modification- routing an additional oil line under the intake manifold. This is not needed for normal street and trail driving but is relevant for anyone building a higher-output 360.
• 2-bolt main caps- stock only: AMC never built a factory 4-bolt main block. Stock 2-bolt mains are entirely adequate for street and trail use at stock output levels. For a built engine producing sustained high power, aftermarket 4-bolt main cap kits are available.
• Aluminum bridged rocker arms from 1974 onward: Post-1974 360s use bridged aluminum rocker arms rather than the earlier individual rocker pedestals. The bridged rockers are less suited to high-performance camshaft upgrades. For a stock replacement, both types are adequate. We note rocker arm type before shipping.
• SAE gross vs net output confusion: The 1970 to 1971 360 was rated at 290 hp SAE gross. From 1972, all outputs were rated SAE net (lower, more accurate numbers measured with accessories installed). The engine did not actually lose that much power in 1972- the rating method changed. A 1972 360 rated at 175 hp SAE net is producing approximately the same actual power as a 1970 360 rated at 245 hp SAE gross in real-world conditions.

AMC 360 by Year and Application

Key milestones across the AMC 360’s 21-year production life:

Common Casting Numbers

Casting number documented before shipping.

What Is Included- What Is Not Included

Vehicle Compatibility

The AMC 360 was factory installed in the following vehicles:

The AMC 304, 360, and 401 all share identical external dimensions, bellhousing bolt pattern, and motor mount locations. The 360 is a direct swap into any vehicle that originally used the 304 or 401. The AMC/Jeep bellhousing pattern is unique- not compatible with GM, Ford, or Chrysler transmissions without an adapter. The Jeep Quadra-Trac, Turbo Hydra-Matic, and various manual transmissions are the correct pairings.

Transmission compatibility: Chrysler Torqueflite A727- standard automatic pairing in most Jeep applications | Turbo Hydra-Matic (early 1970s AMC car applications) | Jeep Quadra-Trac 4WD system | AMC T-18 or T-15 manual | SR4 4-speed manual- some applications. Confirm your specific application before ordering.

Common Names and Search Terms

Used OEM vs Rebuilt- Which Is Right for You?

Used OEM is the right choice for a Grand Wagoneer, Cherokee, or J-series truck restoration where a compression-tested, rear-main-checked engine with casting documentation is the foundation. Our 360 units are documented with year, application, rocker arm type, and rear main seal condition before shipping.

A professionally rebuilt AMC 360 makes sense for a Grand Wagoneer concours restoration or a performance build targeting 300 to 400 hp. AMC/Jeep specialists can rebuild the 360 with fresh tolerances, updated rear main seal conversion to a modern lip seal, and appropriate camshaft. Call us to discuss sourcing options.

Condition and Inspection Process

• Compression test across all 8 cylinders- results per cylinder recorded before shipping
• Rear main seal condition specifically assessed- the AMC 360’s most common failure point inspected and reported
• Year and application confirmed- Jeep vs AMC car application documented, rocker arm type noted (pre-1974 individual vs post-1974 bridged)
• Casting number documented where readable- block year generation noted
• Timing cover and gasket surfaces inspected for seepage
• Valve cover inspection for sludge and cam wear indicators
• Valley area inspected for oil pooling indicators on high-mileage units

Mileage varies by unit. Where available from the donor vehicle we provide it. Where it cannot be confirmed, we disclose this before your order is placed.

Buyer Tips- What to Know Before You Order

• Rear main seal replacement: Any AMC 360 of significant mileage should have the rear main seal replaced at installation. Modern rope seal replacement kits and lip seal conversion kits are available from AMC suppliers (Spitfire, Advance Adapters). The lip seal conversion is a popular upgrade over the original rope seal.
• Modern oil with ZDDP: The AMC 360 uses a flat-tappet hydraulic camshaft. Modern low-zinc oils (SN rating) are insufficient for flat-tappet cam lubrication. Use an oil with ZDDP zinc supplement added or use an oil specifically rated for flat-tappet applications (ZDDP Plus, Driven, or similar).
• Aftermarket support: The AMC 360 has good aftermarket support from suppliers including Melling (oil pumps), Sealed Power (engine rebuild kits), and Edelbrock (intake manifolds and carburetors). Summit Racing and Speedway Motors maintain AMC-specific catalogs. Connect with the AMC community (AMC Forum, Jeep Garage) before building.
• Grand Wagoneer context: A Grand Wagoneer with original matching-number 360 commands a premium in the collector market. If you are sourcing a 360 for a Wagoneer restoration, document the casting numbers of both the engine and the original block for provenance purposes.
• The 304 and 360 are the same stroke: If you need a 360 but find a well-preserved 304, the 304 block cannot become a 360 by changing the bore- the bore spacing on the 304 block allows maximum bore sizes that top out below 360 displacement. They are separate castings.

FAQs

What Jeep vehicles used the AMC 360?