Mopar 360 Engine Specs

Intro

➤ See the Family Page for specs common to all engines in this family.

The Mopar LA 360 is the small-block that spent most of its life being judged for not being a 340, which is a little like criticizing a pickup because it does not corner like a sports car. Introduced for 1971, the 360 was Chrysler’s largest LA small-block, using a 4.000-inch bore and a longer 3.580-inch stroke to make more displacement and more low-speed pull than the smaller members of the family. Its job was torque. Chrysler was not confused about that even if several generations of bench racers were.

That longer stroke is the heart of the engine. The 340 used a larger 4.040-inch bore with the shorter 3.3125-inch stroke and built its reputation around airflow, rpm, and performance-car attitude. The 360 went the other way: slightly less bore, considerably more stroke, and more crank leverage. It was built to move heavier cars, wagons, trucks, vans, police machinery, and whatever else needed a small-block that would pull without requiring the tachometer to file overtime.

The timing did the 360 no favors. It arrived just as high compression, easy horsepower, and gross-rating bragging were heading for the exit. Emissions requirements tightened, compression dropped, net ratings replaced the old numbers, and Detroit started building engines under rules written by people who apparently considered horsepower evidence of moral weakness. The 360 lived through all of it, so plenty of factory examples were mild. The basic architecture did not suddenly become stupid because the carburetor and compression ratio were having a bad decade.

Standard two-barrel versions were honest torque engines. Later four-barrel, E58, police, fleet, and special-duty combinations showed that the 360 could become considerably more interesting when Chrysler surrounded it with the right parts. The Li’l Red Express gave the engine one of its better-known later performance appearances and proved there were still people inside Chrysler willing to let a truck misbehave in public.

That does not mean every 360 with a four-barrel is an E58, police engine, or factory hot rod. Intakes move. Carburetors move. Air cleaners move. Stories move faster than all three. A valuable factory-performance claim needs the year, engine identification, heads, induction, camshaft context, exhaust, application, and supporting evidence to agree before the price starts behaving like it has lights and a siren.

The other thing every 360 owner needs tattooed somewhere visible is external balance. Factory LA 360s require the correct damper and transmission-side balance hardware for the actual rotating assembly. A 318 converter, neutral flywheel, or whatever happened to be lying next to the transmission does not become correct because the bolt holes cooperate. The engine can shake hard enough to make the mistake obvious, but by then the lesson has already become expensive.

For a modern street build, the 360 is one of the easiest LA engines to justify when originality is not controlling the decision. It has useful displacement, real torque, broad application history, and enough parts support to make a strong cruiser or street engine without paying collector money for a 340. It also makes a natural foundation for larger stroker combinations when the entire build is planned around them rather than treated like a kit somebody pours into the block.

The 360 does not need 340 mythology and does not deserve the old “smog motor” dismissal. Build one with compression, camshaft, heads, induction, exhaust, ignition, gearing, converter or clutch, and balance hardware that all understand the assignment, and the extra stroke does exactly what Chrysler intended. A torque engine is allowed to be a torque engine. The tires are unlikely to complain.

↑ Back to the Top, Before the Casting Numbers Start Lying

---

Overview

The 360 arrived for 1971 as the largest displacement in Chrysler’s original LA small-block family. The 273 had started the architecture, the 318 had turned it into the everyday corporate workhorse, and the 340 had established that a small-block Mopar could be genuinely nasty. The 360 was built for the next job: keep the compact LA package, add displacement and torque, and make it useful in the heavier machinery Chrysler increasingly needed to power.

The engine used a 4.000-inch bore and 3.580-inch stroke for 360 cubic inches. Bore spacing remained 4.460 inches and deck height roughly 9.600 inches. The familiar LA pieces stayed in place: cast-iron block and heads, five main bearings, camshaft in the block, pushrods, wedge chambers, shaft-mounted rockers, and a rear distributor.

The bottom end is where the 360 separates itself more sharply from the 273, 318, and 340. Those engines use roughly the same 3.31-inch short-stroke layout and 2.500-inch main journals. The 360 stretches the stroke to 3.580 inches and uses larger 2.810-inch mains. Chrysler did not simply bore another LA larger and change the decal. The crankshaft side of the engine had moved into another neighborhood.

The bore comparison with the 340 is particularly useful because it kills one of the more persistent lazy explanations. The 340 actually has the larger bore at 4.040 inches. The 360 gains its extra displacement from stroke. So calling the 360 “basically a bigger-bore 340” manages to get the important part backward before the sentence has even finished.

That longer stroke gave the 360 its natural advantage: crank leverage and low- to midrange torque. The 340 likes airflow and rpm. The 360 likes moving weight. In a heavier car, truck, van, wagon, cruiser, police package, or ordinary street machine, that can make the larger engine feel stronger where the vehicle spends far more time than it ever will near redline.

The early factory 360 was not introduced as a glamorous muscle engine. Two-barrel versions handled regular passenger-car and service work, and the engine entered production just as compression ratios were dropping and emissions equipment was spreading across engine compartments like somebody had been paid by the hose.

That historical timing explains much of the 360’s uneven reputation. A low-compression engine with mild cam timing, restrictive exhaust, tall gearing, and emissions-era calibration can feel thoroughly unimpressive despite having 360 cubic inches. That is a factory combination problem, not proof the displacement was wasted.

Chrysler later offered stronger four-barrel, E58, police, fleet, and special-duty combinations that made much better use of the engine. The same basic displacement could behave very differently depending on compression, heads, camshaft, carburetion, exhaust, ignition, vehicle weight, converter or clutch, and gearing. The block brings the cubic inches. Everything else decides whether they report for work.

The Li’l Red Express is one of the more memorable examples of the 360 getting a performance-flavored assignment later in the decade. It helped remind people that the engine was capable of considerably more than towing duty when the surrounding vehicle and hardware were chosen with some enthusiasm.

Factory-performance claims still need guardrails. A four-barrel intake does not prove E58. A large carburetor does not prove police service. A truck engine does not become a Li’l Red Express engine because somebody owns red paint. Year, block identity, heads, induction, camshaft context, exhaust, cooling package, application, tags, and paperwork all have to support the particular story being sold.

The 360’s factory external balance is even more important than most of that for somebody trying to make the engine live. The harmonic damper and the transmission-side balance through the converter, flexplate, or flywheel have to match the actual rotating assembly. Chrysler did not add those weights for decoration.

This is where broad LA interchange becomes dangerous. A 318 or early 340 component may physically fit while being completely wrong for the 360’s balance requirement. The transmission can bolt on, the engine can start, and the whole combination can still shake like it has discovered electricity for the first time.

A used 360 therefore needs its rotating hardware identified before anybody starts mixing parts. Check the crank, damper, converter or flywheel, flexplate, and any evidence that a previous machine shop intentionally changed the balance scheme. Factory-style external balance is the baseline, but an aftermarket rotating assembly may have been balanced differently. Assuming is cheaper only until the engine runs.

Car, truck, and van versions add another layer of hardware differences. Oil pans, pickups, mounts, exhaust manifolds, front accessories, cooling pieces, brackets, and other installation parts can follow the original chassis. A complete truck 360 may therefore become remarkably incomplete the moment somebody decides it belongs in a passenger car.

Later LA production introduced roller-cam versions, which can be attractive street-build foundations. Roller hardware can be useful, but the engine still needs to be identified by year, block, heads, cam type, oiling, induction, accessories, and balance arrangement. “Late 360” is a description, not an order form.

The later Magnum 5.9 creates another familiar-name problem. It is a descendant of the same Chrysler small-block line and shares the basic displacement idea, but it brings different heads, intake attachment, pedestal-style rocker hardware, pushrod oiling, valve covers, fuel injection, accessory systems, and engine-management requirements.

A Magnum 5.9 can be an excellent torque engine and useful donor. It is still not simply an LA 360 with the carburetor missing. Mixing LA and Magnum pieces can work when the oiling, pushrods, intake, heads, compression, accessories, and other details are deliberately planned. “Related” continues to be a family-tree word rather than an interchange specification.

Compared with the 318, the 360 brings substantially more stroke and displacement, along with the larger main journals and different balance arrangement. That makes it naturally stronger for torque-oriented street use, especially in heavier vehicles. It also means the rotating assemblies are not generic LA parts waiting to be shuffled between blocks.

Compared with the 340, the 360 gives up some of the big-bore, short-stroke, high-rpm factory personality but gains twenty cubic inches and considerably more stroke. The 340 usually carries more collector and muscle-era prestige. The 360 often makes more practical sense when the assignment is simply to move a street car hard without asking the engine to live at heroic rpm.

That difference matters when money enters the discussion. Paying a 340 premium can be entirely sensible when restoring a real 340 car or when the engine’s identity is part of the reason for the build. Starting with a 360 can be considerably smarter when the goal is ordinary street torque and nobody is grading the car for originality.

The 360 also became a popular foundation for larger stroker combinations because the displacement and block family provide a useful starting point. A common 408-style plan can produce considerably more engine, but the stroker kit does not eliminate the rest of engine building. Block condition, clearance work, rods, pistons, compression, balancing, oiling, heads, camshaft, cooling, converter or clutch, gearing, and drivetrain strength still expect somebody to think before assembly.

A strong conventional 360 needs the same discipline. Compression should match the fuel and heads. Camshaft timing should match the vehicle, gearing, and converter or clutch. Induction should feed the engine rather than impress the neighbors. Exhaust should let the extra displacement breathe. Ignition should arrive when requested. None of those jobs becomes optional because the crankshaft has more leverage.

The wrong combination can waste all the engine’s advantages. Weak compression, too much camshaft, lazy gearing, unsuitable converter, poor exhaust, oversized carburetion, or tired smog-era heads can leave a 360 sounding busy while accomplishing very little. Extra cubic inches are helpful. They are not licensed therapists for bad parts combinations.

Used cores need a proper inspection before the displacement starts making decisions. Look for cracks, freeze damage, bore wear, previous overbores, damaged main saddles, crankshaft wear, thrust damage, lifter-bore wear, deck cuts, broken exhaust bolts, missing balance hardware, wrong transmission pieces, and old machine work. Truck and van engines deserve particular attention because many spent their working lives under heat and load rather than sitting behind velvet ropes.

Completeness can make one core much more valuable than another. Correct pan and pickup, damper, flexplate or flywheel, converter, brackets, pulleys, manifolds, accessory drive, mounts, and other supporting pieces save both money and aggravation. A cheap bare 360 can become remarkably expensive while still sitting on the stand waiting for the parts required to install it.

For a street Mopar with no originality requirement, the 360 often lands in the sweet spot of the LA family. It has more displacement than the 318, avoids much of the collector premium surrounding the 340, and naturally produces the kind of torque most cruisers and street cars actually use.

That does not make it the right answer for everything. A correct 340 car may deserve its original engine. A mild cruiser may already have a perfectly healthy 318 that needs nothing more. A Magnum-based project may make more sense with an actual Magnum. Choosing the engine that fits the mission usually costs less than choosing the famous number and forcing the rest of the car to cooperate.

The 360’s reputation improves considerably once it stops being compared with engines assigned different jobs. It was Chrysler’s long-stroke, big-displacement LA torque engine, built through passenger-car, truck, van, police, emissions, roller-cam, and later electronic-fuel-system eras. That long working life says more about the architecture than the weakest smog-era horsepower rating ever printed beside it.

So judge the 360 by the actual engine sitting there. Identify the year and application. Verify the balance hardware. Know whether it is early LA, later roller LA, or something being confused with a Magnum 5.9. Check its condition and completeness. Then build around torque instead of trying to turn it into whatever somebody remembers liking about a 340.

The 360 does not need borrowed glory. It already has more stroke, more cubes, plenty of useful pull, and one of the strongest practical arguments in the LA family. Give it the right parts and let the crankshaft do its job. Chrysler already supplied the leverage.

↑ Back to the Top, Before the Casting Numbers Start Lying

---

General Specs

Displacement	360 cu in / 5.9L	Bore / Stroke	4.000 in × 3.580 in
Production / Use Era	1971–1992 Mopar LA small-block passenger-car and light-truck era	Bore Spacing	4.460 in
Engine Family	Chrysler / Mopar LA-series small-block wedge V8	Deck Height	9.600 in LA small-block baseline
Block Material	Cast iron	Rod Length	6.123 in LA small-block baseline
Cylinder Head Material	Cast iron	Main Journal	2.810 in
Factory Rating / Strength Lane	Torque-heavy small-block workhorse lane; ranges from mild 2-barrel cruiser and truck duty to stronger 4-barrel, E58, police, and special-duty applications	Compression Ratio	Early, emissions-era, truck, police, E58, roller-cam, and TBI-era versions need exact year, piston, head, cam, and application verification
Fuel / Induction	Gasoline; carbureted or throttle-body EFI by year and application	Rod Journal	2.125 in
Cam Location	In-block camshaft	Main Bearings	5
Valve Layout	OHV / pushrod, 2 valves per cylinder; wedge chambers	Firing Order	1-8-4-3-6-5-7-2
Common Main Caps	2-bolt	Distributor Rotation	Clockwise
Rear Main Seal	2-piece	Balance	External balance in factory LA 360 form; damper, converter, flexplate, flywheel, and rotating assembly must match the actual engine
Weight	~500–550 lb complete iron LA small-block with typical accessories	Dimensions	~28H / ~26W / ~29L
Primary Identity Check	Verify 4.000-inch bore, 3.580-inch stroke, 360 crank, external-balance hardware, oil pan, pickup, block casting, stampings, heads, and application before ordering parts	Common Use	Passenger cars, trucks, vans, police packages, fleet service, street builds, swaps, cruisers, towing-minded builds, and 408 stroker foundations

Verify the block, bore, crank, heads, intake, carburetion or TBI pieces, camshaft, compression, balance hardware, converter or flywheel fit, oil pan, pickup, front dress, stampings, dates, and vehicle application before ordering parts. A 360 can be one of the smartest LA small-block choices in the garage. It can also shake the lesson into the floorpan when the balance parts come from the wrong pile.

↑ Back to the Top, Before the Casting Numbers Start Lying

---

Variants

The 360 spent enough years in enough vehicles to make its history look messier than the actual engine choices. Underneath, every LA 360 starts with the same important architecture: 4.000-inch bore, 3.580-inch stroke, larger 2.810-inch main journals, and factory external balance. The useful hardware split is the ordinary two-barrel engine, the stronger factory four-barrel / E58 / police combinations, and the later roller-cam LA version. Truck brackets, emissions plumbing, and somebody else’s carburetor do not need their own place in the family tree.

Standard 360 — Two-Barrel

What it was: This was the ordinary production 360 and the version that established the engine as Chrysler’s long-stroke torque small-block.

What changed: Standard engines used two-barrel carburetion with mild cam timing, street-oriented heads and exhaust, and the lower-compression calibration common to much of the 360’s early emissions-era production.

What that did: The 3.580-inch stroke gave the 360 useful low- and midrange pull without asking the engine to spin like a 340. In a heavy car, wagon, truck, or van, that extra crank leverage did exactly what Chrysler wanted. It moved weight. Nobody at the engineering meeting was worried that some fellow fifty years later might call it a smog motor because the quarter-mile number failed to make him emotional.

Where used: Passenger cars, wagons, trucks, vans, fleet vehicles, and other regular-production 360 applications.

Factory Four-Barrel / E58 / Police 360

What it was: These were the stronger factory versions that showed what the 360 could do once Chrysler stopped feeding it through the ordinary two-barrel hardware.

What changed: Depending on year and application, Chrysler added four-barrel induction, more performance-oriented camshaft and ignition calibration, freer exhaust, improved cooling, and other police, E58, fleet, or special-duty supporting hardware.

What that did: More airflow and better supporting equipment let the extra displacement work considerably harder. The 360 still made its best argument with torque rather than heroic rpm, which made these combinations particularly effective in real street cars and heavier police machinery. Twenty more cubic inches than a 340 do not automatically make a better engine, but they certainly do not hurt when the rest of the parts have finally been invited to work.

Where used: Factory four-barrel passenger-car applications, E58 performance packages, police and pursuit vehicles, fleet-duty combinations, and selected special-duty 360 applications.

Identification caution: This claim earns inspection because four-barrel intakes and police stories migrate freely. Engine stamping, casting dates, heads, intake, carburetor, camshaft context, exhaust, cooling equipment, application, tags, drivetrain, and surviving paperwork need to support an E58, police, or other factory-performance claim. A Thermo-Quad and a big radiator are parts, not sworn witnesses.

Later Roller-Cam LA 360

What it was: Late LA production brought a meaningful valvetrain change before Chrysler moved fully into the Magnum 5.9 era.

What changed: Chrysler adopted roller-cam hardware while retaining the traditional LA-family block architecture and 360 displacement. Depending on application, these later engines could also carry different induction, electronic controls, accessory drives, and truck-oriented external hardware.

What that did: The roller valvetrain reduced the sliding friction and flat-tappet wear concerns of the earlier setup and gives a later LA block some genuine appeal as a street-build foundation. It is still a 360 torque engine underneath. Roller lifters did not suddenly convince the 3.580-inch stroke that it wanted a 340’s personality.

Where used: Later LA-series truck, van, and related production applications before the Magnum 5.9 replaced the traditional LA version.

The emissions-era and truck-duty engines do not need another mechanical variant heading simply because compression, carburetion, emissions equipment, oil pans, mounts, manifolds, cooling pieces, and brackets changed with year and chassis. Those details matter when buying or swapping one, but most are application equipment surrounding the same basic 360 long block.

One rule applies to every factory LA 360: external balance. The correct damper and transmission-side balance hardware have to match the rotating assembly. A neutral-balance 318 converter, flywheel, or whatever happened to be leaning against the workbench does not become correct when the bolts line up. The engine will eventually provide its own rather vigorous technical explanation.

And keep the Magnum 5.9 outside this variant ladder. It descends from the same Chrysler small-block family and carries the same basic displacement, but its heads, intake attachment, rocker system, pushrod oiling, fuel injection, valve covers, accessories, and engine-management hardware make it another generation rather than a late LA 360 variant.

So the factory LA 360 map stays useful: standard two-barrel torque engine, genuine four-barrel / E58 / police hardware, and the later roller-cam LA. The 360 does not need borrowed 340 glory or Magnum identity. Chrysler gave it more stroke, more cubes, and enough crank leverage to make a very good street engine once somebody quits apologizing for what it was built to do.

↑ Back to the Top, Before the Casting Numbers Start Lying

---

Key Notes

The LA 360 is the torque-heavy Mopar small-block, not a cheap 340, not a stretched 318, and not automatically a Magnum 5.9 because the displacement survived into the next era. It has its own stroke, balance rules, factory history, and very useful personality when nobody asks it to be something else.

The basic fingerprint is 360 cubic inches from a 4.000-inch bore and 3.580-inch stroke. That longer stroke is the heart of the engine. Compared with a 340, the 360 gives up some short-stroke snap but brings more torque cushion. Compared with a 318, it has more displacement and more pull. That isn’t magic. That’s cubic inches and leverage doing their dirty little job.

The 360’s value starts with torque. It can move heavier cars, trucks, vans, cruisers, tow-minded projects, and street builds without begging for rpm. The 340 may have the sharper factory performance image, and the 318 may be the common workhorse, but the 360 brings the extra arm. Used honestly, that makes it one of the most practical LA small-block choices.

The first buyer mistake is treating every 360 as the same animal. A 1971 2-barrel passenger-car engine, an E58-style 4-barrel, a police package, a truck engine, a later roller-cam LA, a TBI-era engine, and a Magnum 5.9 can all wear the 360 / 5.9 idea while bringing different parts problems to the bench. Same cubes, different homework.

The second mistake is confusing the 360 with its LA relatives. A 318 can be a fine workhorse, but it doesn’t share the 360’s stroke, main-journal size, external-balance setup, oil pan logic, or torque personality. A 340 can be the more valuable performance-era piece, but it doesn’t share the 360’s longer-stroke mission. Same family, different troublemaker.

The third split is LA 360 versus Magnum 5.9. The Magnum came later with different heads, pushrod oiling, valve covers, intake pattern, fuel-injection hardware, accessory layout, and EFI-era parts logic. A Magnum 5.9 can be a strong engine. It’s not just an LA 360 with newer stickers, and mixing those parts without understanding the rules is how projects start developing a permanent limp.

External balance is the warning that deserves to wear a bright orange vest. Factory LA 360s need the correct damper, converter, flexplate, flywheel, and rotating assembly match. A transmission can bolt up and still be wrong. A converter can fit and still make the engine shake like it’s trying to jump out and find a smarter owner.

Factory performance claims need proof, but not panic. Four-barrel, E58, police, Li’l Red Express, fleet, and special-duty stories can all raise interest. They don’t prove themselves with a carburetor, a badge, or a seller who suddenly remembers the word “pursuit.” The year, block, heads, intake, carburetion, exhaust, cooling package, balance parts, application, and paperwork need to agree before the price starts doing push-ups.

As a street engine, the 360 is easy to justify. It has useful torque, good displacement, decent bore size, and enough parts support to build a strong cruiser or street engine without paying 340 nostalgia tax. It likes a sensible cam, compression that matches the fuel and heads, decent induction, good exhaust, proper ignition, and gearing that uses torque instead of pretending every stoplight is a road-race qualifying session.

That doesn’t make every 360 build smart. Low compression, lazy smog heads, too much cam, wrong converter, weak exhaust, mismatched carburetion, and ignored balance parts can make a 360 feel dull, rough, or expensive for no good reason. The extra stroke helps. It doesn’t absolve bad planning.

Parts support is good, but the 360 isn’t a 318 / 340 parts dump. Heads, intake, camshaft, pistons, balancer, flywheel or converter, flexplate, oil pan, pickup, brackets, pulleys, timing cover, water pump, and year-specific pieces can change the job. A cheap 360 can get expensive fast when the balance and fitment pieces are wrong.

Interchange needs discipline because the 360 tempts people into lazy LA-family thinking. Some 318, 340, and Magnum parts can be useful in the right combination, but compression, chamber size, port size, pushrod oiling, intake fit, balance, accessory layout, and intended use still decide the plan. Don’t assume 340 heads make a 360 a 340. Don’t assume Magnum parts fix LA problems without bringing Magnum rules with them.

A used 360 core needs inspection before anyone celebrates the cubic inches. Check for cracks, freeze damage, cylinder-wall wear, overbore history, main saddle condition, crank damage, thrust wear, lifter-bore wear, deck cuts, broken exhaust bolts, missing balance parts, wrong converter or flexplate, missing oil pan, missing brackets, and previous rebuild work done by somebody who thought sealant was a structural material.

The 360 belongs in the practical-torque LA lane, not the budget-340 fantasy and not the smog-era reject pile. If the goal is a strong street car, truck, cruiser, or budget Mopar with real low- and mid-range pull, the 360 can be the right answer. If the goal is original 340 value, matching-numbers collector money, or a lazy pile of mismatched parts, the 360 won’t fix the thinking. The engine has muscle. The plan still needs a brain.

↑ Back to the Top, Before the Casting Numbers Start Lying

---

Bottom Line

The Mopar LA 360 is the torque engine of the family, and that is the job it should be judged by. The 340 got the sharper muscle-era reputation, while the 360 brought more stroke, more displacement, and more low-speed pull for heavier cars, trucks, vans, police packages, and ordinary street use. It was never a failed 340. It was Chrysler answering a different question.

That makes a healthy 360 one of the smarter practical Mopar small-block choices when street torque matters more than collector bragging rights. It can move a heavier car well, make a strong cruiser, serve truck or towing duty, or become a serious street foundation without dragging big-block weight along for the ride. It does not need to rev like a 340 to feel strong where most street engines actually spend their time.

The 360 also makes sense when the car needs performance but not 340 identity. A correct 340 car deserves a 340 when originality and value matter, but a driver or street build may be better served by the 360’s displacement and torque. Paying collector money for a famous number makes little sense when the job only requires an engine that pulls hard and behaves itself.

The trap is assuming every LA small-block part belongs on every LA small-block. The 360 has enough of its own balance and supporting-hardware requirements to punish casual parts mixing. A cheap core becomes less cheap when the wrong converter, flexplate, flywheel, damper, pan, or other mismatched hardware starts creating problems. “It bolts on” is not the same thing as “it belongs there,” and the 360 is particularly good at demonstrating the difference.

So build the 360 when torque, drivability, and small-block packaging fit the mission, and judge the actual engine by condition rather than old smog-era reputation. A sound, complete 360 can be one of Mopar’s best street foundations. A tired mystery core with mixed parts can shake both the car and the wallet apart. The 360 does not need 340 mythology to be good. It just needs the right parts, the right combination, and somebody willing to let a torque engine be a torque engine.

↑ Back to the Top, Before the Casting Numbers Start Lying

---