How Heavy Is an Engine? Weight by Type, Material, and Real Specs

A LS3 6.2-liter V8 sits on a stand at 445 pounds. A Honda K20 four-cylinder, pulled bare from a Civic Si, weighs 275. A Cummins 6.7 turbodiesel out of a Ram 2500 tips the engine hoist at 1,100. Three engines, three different worlds, all sold in production cars over the same model year. The question of how heavy is an engine has the kind of answer that sounds simple in a sentence and gets complicated the moment a real shop tries to lift one out of a truck. The number on the scale depends on the configuration, the block material, the accessory load, the fluids, and whether the seller is quoting a long block, a short block, or the bare casting that came off the foundry line.

This guide pulls the working ranges for every common engine class, names specific OEM engines with verified weights, separates dressed from bare numbers so the comparisons line up, and explains where engine weight starts to bite a real driver: front-axle balance, fuel economy, brake load, and engine-swap math.

How Heavy Is an Engine?

Most production car and light-truck engines weigh between 200 and 700 pounds. A modern aluminum four-cylinder runs 200 to 350 lb. A V6 lands at 350 to 450 lb. An aluminum V8 sits at 400 to 500 lb. A cast-iron V8 climbs to 550 to 700 lb. A medium-duty diesel pickup engine weighs 950 to 1,150 lb. An EV drive unit (the equivalent rotating component on an electric car) weighs 100 to 250 lb.

Those ranges cover the long block: the assembled engine with cylinder head, intake, exhaust manifolds, and accessory mounts, but without the fluids, the transmission, or the wiring harness. A fully dressed engine with all accessories and fluids adds another 75 to 150 lb on top of the long block.

Check Out the Different Types of Engines Used in Cars:

Engine Weight by Configuration Chart

The figures pull from manufacturer published spec sheets, verified shop-scale numbers from build threads on F150 Forum, LS1Tech, and Mustang6G, and crate-engine retailer listings from Summit Racing, JEGS, and Ford Performance Parts. Exact weight varies by accessory configuration and fluid load, so the ranges represent typical long-block deliveries rather than a single point.

Bare Block, Long Block, and Fully Dressed: Why the Numbers Disagree

Check Out Understanding Engine Size… Applying Volume of a Cylinder:

Half the confusion in engine-weight forums comes from people comparing different states of the same engine. A bare aluminum LS block weighs roughly 110 lb. The same engine fully dressed and ready to drop into a chassis weighs more than five times that.

The standard states, from lightest to heaviest:

• Bare block. Just the cylinder block casting. No crank, no heads, no internals. An LS aluminum bare block weighs about 110 lb. An iron 5.3 Vortec bare block weighs roughly 215 lb.
• Short block. Block plus crank, rods, pistons, and bearings. Add 60 to 90 lb to the bare block.
• Long block. Short block plus cylinder heads, valvetrain, and timing components. The most commonly quoted “engine weight” number. An LS3 long block is about 445 lb.
• Dressed engine. Long block plus intake manifold, exhaust manifolds, accessory drive (alternator, AC compressor, power steering pump, water pump), and ECU. Add 50 to 90 lb.
• Fully wet engine. Dressed engine with all fluids: coolant, oil, ATF in the converter if attached. Add 30 to 60 lb.

Numbers reported on enthusiast forums are usually long-block or dressed-without-fluids weights. Numbers from a junkyard are usually fully dressed because the engine is pulled with the harness and accessories still on it. Numbers from a crate-engine listing depend on how the seller defines the package. Asking which state is being measured is the first question before comparing two engines.

Wrench-Tech Tip: A 5.7 Hemi base engine is often quoted at 485 lb, but a fully dressed 5.7 Hemi pulled from a Ram 1500 with all accessories and fluids is closer to 560 lb. That 75 lb gap is the accessory pack, not a different engine. The same gap shows up on every modern V8.

Four-Cylinder Engine Weight

Modern four-cylinder engines are mostly aluminum block and aluminum head, and the weight ranges have tightened since the 1990s as iron blocks left the segment. A Honda K20 weighs about 275 lb bare, climbing to 405 lb fully dressed with the accessory drive and intake. A Toyota 2AR-FE 2.5 four-cylinder weighs around 300 lb. A Subaru EJ20 turbocharged flat-four (technically a boxer-four, not an inline) sits at 350 to 380 lb because the boxer architecture trades vertical compactness for lateral width and a heavier crankcase.

Older iron-block four-cylinders run heavier. The GM Iron Duke 2.5, used in 1980s and 1990s GM compacts and Jeep Wranglers, weighs 350 to 400 lb depending on the year. The Jeep AMC 2.5 four runs in the same range. Both feel disproportionate next to a modern aluminum design putting out twice the horsepower at three-quarters of the weight.

For an engine-swap context, a turbocharged aluminum four like the Honda K20A2 or a Subaru EJ257 lands in the same weight class as a non-turbocharged Honda K24, which is part of why those swaps work in lightweight chassis like Miatas and BRZs without dramatically altering the front-axle balance.

V6 Engine Weight

V6 engines spread across a wider range than four-cylinders because the segment includes both lightweight aluminum overhead-cam V6s aimed at front-drive cars and older iron-block pushrod V6s used in trucks and rear-drive applications.

A modern aluminum V6 typically weighs 350 to 450 lb. The Toyota 2GR-FE 3.5 V6, used in Camry, Avalon, RAV4, and several Lexus models, weighs about 359 lb dressed. The Ford 3.5 EcoBoost twin-turbo V6 used in the F-150 and Raptor sits at 449 lb bare, climbing into the 550 to 600 lb range fully dressed with intercoolers, turbos, and accessory drive. The Honda J35 3.5 V6 lands around 380 to 420 lb.

Older iron-block V6 designs run heavier. The Buick 3800 Series II V6, used across two decades of GM front-drive cars, weighs 425 to 480 lb fully dressed. The Ford Vulcan 3.0 V6 is in the same range. A pushrod GM 4.3 Vortec V6 (essentially a small-block Chevy V8 with two cylinders missing) weighs 425 to 450 lb dressed.

The V6 weight band overlaps the aluminum-V8 band on the high end, which is why a 3.5 EcoBoost dressed engine and an aluminum LS V8 long block end up within 50 lb of each other despite the V8 having two more cylinders.

V8 Engine Weight

V8 weight is where engine-swap math gets serious, because the V8 segment includes both modern aluminum performance engines that weigh less than a 1990s iron V6 and old-school big-blocks that weigh as much as some diesel engines.

The aluminum-block, aluminum-head modern performance V8s are the surprise of the segment. The GM LS1 weighs about 430 lb. The LS3 6.2 weighs 445 lb. The LS7 7.0 weighs 387 lb in its lightweight Z06 trim, which makes it lighter than a stock 2GR-FE V6. The Ford Coyote 5.0 weighs in at 430 lb without water pump, with flywheel. The current Gen V LT1 from a Camaro SS lands in the same band.

Iron-block V8s with aluminum heads sit one tier heavier. The 5.7 Hemi base engine weighs 485 lb, climbing to 560 lb fully dressed in a Ram 1500. The older Vortec 5.3 iron block with aluminum heads runs 525 to 550 lb. The classic small-block Chevy 350 with iron heads weighs 575 to 605 lb depending on accessory load.

Big-block V8s climb again. The Chevrolet 396, 427, and 454 big-blocks weigh 650 to 700 lb dressed. The Ford 429/460 sits at 700 to 720 lb. A cast-iron all-iron Chevy 454 with iron heads pushes 754 lb on a verified scale. Chrysler’s old 426 race Hemi weighs 845 lb, which is in diesel-engine territory.

The takeaway most relevant to an engine swap: an LS-series aluminum V8 weighs less than a small-block Chevy by 100 to 150 lb, and less than a big-block by 200 to 300 lb. That is the entire mechanical case for the LS swap into a 1960s muscle car or a classic truck. The chassis was designed around iron-block weight; replacing it with aluminum shifts weight bias rearward and improves both handling and braking.

Inline-6 Engine Weight

Inline-six engines run a different geometry than V-engines and end up in their own weight band. The architecture is naturally balanced (no balance shafts needed), which means the block can be lighter than a comparable V8 of similar displacement, but the long crankshaft and longer block add length-driven weight elsewhere.

A modern aluminum BMW B58 3.0 inline-six weighs about 425 to 450 lb dressed. The Toyota 2JZ-GTE turbocharged 3.0 inline-six, the engine that built the Supra reputation, weighs roughly 580 lb fully dressed because the iron block adds significant mass over an aluminum equivalent. The Jeep 4.0 inline-six, used in Wranglers and Cherokees through 2006, weighs 530 to 560 lb. The Ford 300 inline-six (the 1965-1996 truck engine) weighs about 510 lb.

Mercedes-Benz returned to inline-six architecture with the M256 in 2018 (3.0 turbo), partly because the modular four-cylinder-plus-two-cylinder approach lets them share manufacturing tooling. The M256 weighs about 410 lb dressed.

Diesel Engine Weight

Diesel engines are heavier than gasoline engines of the same displacement because diesel’s higher compression ratio (typically 16:1 to 22:1 vs 9:1 to 11:1 for gasoline) demands a stronger block, heavier crank, heavier rods, and more substantial cylinder head. A diesel pickup engine weighs roughly twice what a gasoline V8 of the same displacement weighs.

The three production diesel pickup engines in the North American market and their dressed weights:

• Cummins 6.7 turbodiesel I6. Used in Ram 2500/3500. Weighs roughly 1,100 lb fully dressed. The previous 5.9 Cummins is in the same weight class because the displacement bump came mostly from a longer stroke, not a heavier block.
• Ford Power Stroke 6.7 turbodiesel V8. Used in Super Duty F-250/F-350/F-450. Weighs about 990 lb dressed. The V8 architecture saves length over the Cummins inline-six, but adds weight at the cylinder head.
• GM Duramax 6.6 turbodiesel V8. Used in Silverado 2500/3500 and Sierra HD. Dressed weight runs 835 to 880 lb depending on generation (LBZ, LML, LMM, L5P). The Duramax is the lightest of the three by a meaningful margin, partly because of the aluminum cylinder heads on later generations. The full breakdown of Duramax engine weight by generation covers the LBZ, LMM, LML, and L5P deltas.

Smaller diesel engines used in light-duty pickups and SUVs weigh less but still run heavier than their gasoline counterparts. The Ram 1500 EcoDiesel 3.0 V6 weighs 700 to 750 lb dressed. The VW 3.0 TDI V6 used in Touareg and Audi Q7 weighs roughly 540 lb. The VW 2.0 TDI four-cylinder, used across millions of European Golfs and Jettas, weighs about 350 lb, which is heavier than the gasoline 2.0 TSI by 60 to 80 lb at the same displacement.

The weight penalty is the trade for diesel’s torque output and fuel economy. On a heavy-duty pickup pulling a fifth-wheel trailer, the 1,100 lb under the hood is a feature, not a bug, because it puts the front axle weight where it needs to be for towing stability.

EV Drive Unit Weight: How an Electric Motor Compares

The transition to electric vehicles has reshaped the weight conversation, because the EV equivalent of an engine is dramatically lighter than the engine it replaces, while the battery pack adds weight elsewhere.

A typical EV drive unit, which combines an electric motor, a single-speed gearbox, and the inverter electronics, weighs 100 to 250 lb. The Tesla Model 3 rear drive unit weighs about 200 lb. The Chevrolet Bolt drive unit weighs roughly 165 lb. The Tesla Model S Plaid front drive unit, which puts out more than 600 horsepower, weighs about 175 lb.

That puts an EV motor at one-third to one-half the weight of an aluminum V6 producing similar power. The catch is the battery pack: a Tesla Model 3 Long Range battery weighs about 1,060 lb, and a Lucid Air Grand Touring battery pushes 1,500 lb. The companion writeup on how much an EV battery weighs breaks down pack weight by manufacturer and generation.

The vehicle-level math ends up close. A 2024 Honda Civic weighs about 2,950 lb. A 2024 Tesla Model 3 weighs 3,890 lb. The Tesla replaces a 350 lb engine with a 200 lb motor (saves 150 lb) but adds a 1,000 lb battery pack (gains 1,000 lb), so the EV ends up about 950 lb heavier than the comparable gasoline car. The weight is just distributed differently: low and centered in the EV, high and forward in the gasoline car.

What Drives Engine Weight

Five variables explain almost every difference between two engines on the scale:

Block material. Cast iron is roughly 2.5 times denser than aluminum. An iron-block V8 weighs 100 to 200 lb more than the same engine cast in aluminum. The 5.3 Vortec is available in both iron-block (older trucks, retained for cost) and aluminum-block (LS-derived L83, used in Silverado 1500) variants, with the iron version weighing 150 lb more.

Cylinder count and configuration. Each additional cylinder adds a piston, a connecting rod, two valves (or four, on a DOHC engine), and the block material to enclose them. A V8 weighs roughly 1.5 to 1.8 times what a four-cylinder of similar bore and stroke weighs. The configuration also matters: a V-engine is shorter and wider than an inline of the same cylinder count, which trades length-driven weight for width-driven weight at roughly equivalent totals.

Displacement and bore. A larger bore needs a thicker cylinder wall, longer stroke, longer connecting rods, and a longer block. A 5.0 V8 typically weighs 50 to 80 lb more than a 4.6 V8 of the same family.

Forced induction. Turbocharged and supercharged engines add 30 to 80 lb for the boost hardware: turbos, intercoolers, intake plumbing, oil supply lines. The 3.5 EcoBoost weighs 100 lb more dressed than a naturally aspirated 3.5 V6 because of the twin-turbo system.

Accessory load. Air conditioning compressors, alternators, power steering pumps (or electric power steering, which moves weight off the engine), starter motors, and emissions hardware add 50 to 90 lb to a fully dressed engine. A bare engine doesn’t reflect what actually drops into a chassis.

Why Engine Weight Matters

Engine weight shows up in four places that affect how a vehicle drives and how it’s serviced.

Front-axle balance. A heavier engine puts more weight over the front wheels, which on a front-engine, rear-drive car means more understeer, more front brake load, and more front tire wear. The case for an LS swap into a 1960s muscle car is partly the horsepower-per-pound improvement and partly the front-rear balance shift that comes from dropping 150 lb off the front axle. On a front-engine front-drive economy car, the weight is already over the drive wheels, so a lighter engine reduces tire wear without changing balance dramatically.

Fuel economy. Vehicle weight is the single biggest controllable input to fuel consumption at city speeds. The engine is a big chunk of total vehicle weight. On a 3,500 lb sedan, a 100 lb engine weight reduction (via aluminum block instead of iron) is roughly a 3 percent vehicle weight reduction, which translates to a 1 to 2 percent city fuel economy improvement. The OEM math behind switching to aluminum blocks across modern production is dominated by the fuel-economy and CAFE-compliance side, not the performance side. The historical gas-price record by year is part of why those CAFE numbers move every product cycle.

Brake load. Heavier vehicles need more brake capacity to stop in the same distance. A heavy diesel pickup with a 1,100 lb engine, a heavy-duty transmission, and a 4WD transfer case has roughly 2,000 lb of drivetrain on the front axle alone, which is why Super Duty trucks run 14-inch front rotors and four-piston calipers as standard. A lighter engine reduces the brake spec the chassis has to carry.

Engine-swap math. For anyone planning a swap, the engine weight number is the difference between bolting the new engine to the existing K-member and motor mounts (close to original weight) and re-engineering the front suspension (50 to 100 lb heavier). Swapping a 5.7 Hemi (560 lb dressed) into a chassis built for an iron-block 5.7 small-block (605 lb dressed) is a near-zero net change. Swapping an LS V8 (430 lb) into a chassis built for a 350 ci small block (605 lb) drops 175 lb off the front axle, which is enough to require a re-corner on the alignment and possibly a softer front spring rate to keep ride height neutral.

If the engine seems to be running heavy in another sense, like loss of power under load, that’s a separate diagnostic problem. The breakdown on why a car loses power covers compressor drag, intake restriction, and the seven faults that turn a healthy engine into a sluggish one without changing its weight.

How to Find the Weight of a Specific Engine

Three sources, in order of reliability:

1. Manufacturer service manual or crate-engine spec sheet. OEM service manuals list engine weight in the specifications section, usually in pounds for North American markets and kilograms for European markets. Crate-engine pages on Ford Performance Parts, GM Performance Parts, and Mopar Direct Connection list dressed weight on every SKU.
2. Verified forum scale numbers. Build threads on F150 Forum, LS1Tech, Mustang6G, NASIOC, and Spyder Chat regularly include shop-scale verified numbers from owners who actually weighed the engine before installing it. Cross-check at least two threads before trusting a single post, because some posts mix bare-block with dressed weights.
3. Engine-swap vendor catalogs. Companies like ICT Billet, BRP Hot Rods, and Holley publish swap dimension and weight specs for the engines they sell adapter plates and motor mounts for. The numbers are usually long-block or dressed weights and tend to be conservative.

The number on the scale at a junkyard counter is the least reliable source because the engine is often pulled with the transmission, the bell housing, or even the K-member still attached. Asking what’s included before paying for the engine is the only way to back into a clean engine-only weight.

How Heavy Is an Engine: Quick Reference Numbers

Round numbers to remember when budgeting an engine swap, planning a rebuild, or talking through a chassis math problem:

• Modern aluminum 4-cylinder: 250 to 350 lb
• Modern aluminum V6: 350 to 450 lb
• Aluminum V8 (LS, Coyote, modern Mod): 400 to 500 lb
• Iron-block V8 with aluminum heads: 500 to 600 lb
• Cast-iron small-block V8: 550 to 650 lb
• Cast-iron big-block V8: 650 to 800 lb
• Diesel I6 (HD pickup): 950 to 1,150 lb
• Diesel V8 (HD pickup): 800 to 1,000 lb
• EV drive unit (motor + gearbox + inverter): 100 to 250 lb

A useful rule of thumb is that a pound of engine weight costs roughly the same in fuel economy as a pound of any other weight on the vehicle, but it costs more in brake load and front-axle wear because of where it sits on the chassis. The ranges above hold for nearly every production engine sold in the last forty years. The exceptions, like the 845 lb 426 race Hemi or the 175 lb Tesla Plaid drive unit, are interesting outliers but not where most builds live.

Engine Weight FAQs

How heavy is an engine on average?

An average modern car engine weighs 350 to 500 pounds. A four-cylinder runs 250 to 350 lb, a V6 runs 350 to 450 lb, and an aluminum V8 runs 400 to 500 lb. Iron-block V8s are heavier (550 to 700 lb), and heavy-duty diesel pickup engines climb to 950 to 1,150 lb. The exact weight depends on the block material, displacement, accessory load, and whether the seller is quoting a long block or a fully dressed engine.

How much does a V8 engine weigh?

A V8 engine weighs 400 to 800 pounds depending on materials and design. A modern aluminum V8 like the LS3 or Coyote 5.0 weighs about 430 to 445 lb. An iron-block V8 with aluminum heads like the 5.7 Hemi weighs 485 to 560 lb dressed. A traditional cast-iron small-block (Chevy 350, Ford 302) weighs 575 to 605 lb. A cast-iron big-block (Chevy 454, Ford 460) climbs to 650 to 800 lb. The aluminum V8 weight savings is the entire mechanical case for an LS swap into older muscle cars and trucks.

How much does a 4-cylinder engine weigh?

A modern 4-cylinder engine weighs 250 to 350 pounds. The Honda K20 weighs about 275 lb bare, a Toyota 2AR-FE 2.5 weighs around 300 lb, and a turbocharged Subaru EJ20 boxer-four sits at 350 to 380 lb. Older iron-block four-cylinders like the GM Iron Duke run 350 to 400 lb. The weight band has tightened over the last twenty years as iron blocks left the segment.

How much does a diesel engine weigh?

A heavy-duty pickup diesel engine weighs 800 to 1,150 pounds. A Cummins 6.7 inline-six weighs roughly 1,100 lb dressed. A Ford Power Stroke 6.7 V8 weighs about 990 lb. A GM Duramax 6.6 V8 weighs 835 to 880 lb depending on generation. Light-duty diesel V6s like the Ram EcoDiesel 3.0 run 700 to 750 lb. The diesel weight penalty is the trade for higher compression, more torque, and better fuel economy on heavy-duty work cycles.

Is an aluminum engine block lighter than cast iron?

Yes, by a wide margin. Cast iron is roughly 2.5 times denser than aluminum. An iron-block V8 weighs 100 to 200 lb more than the same design cast in aluminum. A bare aluminum LS block weighs about 110 lb. A bare iron 5.3 Vortec block weighs around 215 lb. The weight savings is why almost all modern production passenger-car engines use aluminum blocks despite the higher casting cost and the need for cylinder liners.

How heavy is an electric car motor compared to a gasoline engine?

An EV drive unit weighs 100 to 250 pounds, which is one-third to one-half the weight of a comparable gasoline engine. A Tesla Model 3 rear drive unit weighs about 200 lb, and a Chevy Bolt drive unit weighs around 165 lb. The catch is the battery pack: an EV battery weighs 1,000 to 1,500 lb, which more than offsets the motor savings. Total vehicle weight for an EV is typically 800 to 1,200 lb higher than a comparable gasoline car.

Does engine weight affect fuel economy?

Yes. Engine weight is part of total vehicle weight, and vehicle weight is the single biggest controllable input to fuel consumption at city speeds. A 100 lb engine weight reduction on a 3,500 lb sedan is about a 3 percent vehicle weight reduction, which translates to a 1 to 2 percent city fuel economy improvement. The OEM business case for switching to aluminum blocks is dominated by fuel economy and CAFE compliance, not by performance.

Why is the same engine listed at different weights on different sites?

Because different sites quote different states of the engine. A bare block weighs the least. A short block adds the rotating assembly. A long block adds the heads and valvetrain. A dressed engine adds the intake, exhaust manifolds, and accessory drive. A fully wet engine adds the fluids. The gap between a bare block and a fully wet engine on a modern V8 is more than 300 lb. Always check which state the seller or forum is quoting before comparing two numbers.

How heavy is a Cummins 6.7 engine?

A Cummins 6.7 turbodiesel inline-six, used in Ram 2500 and 3500 pickups, weighs roughly 1,100 pounds fully dressed. That includes the turbocharger, the intercooler plumbing, the high-pressure fuel system, and the accessory drive. The bare engine without the accessory pack weighs about 1,000 lb. The 5.9 Cummins that preceded it lands in the same weight class because the displacement bump came from a longer stroke rather than a heavier block.

The Practical Takeaway

How heavy is an engine ends up being the wrong question to lead with on most builds. The right question is how heavy a specific engine is in a specific configuration, because the spread between a bare aluminum LS block at 110 lb and a fully dressed Cummins 6.7 at 1,100 lb is ten to one. Knowing the working ranges by configuration and the dressed-versus-bare distinction is what makes a swap calculation, a rebuild budget, or a chassis-balance decision actually work out on the scale.

For broader engine-related diagnostics and rebuild context, the AxleWise engine and drivetrain hub collects the related guides on swaps, rebuilds, and weight-driven service decisions. The companion piece on why milky oil shows up in an engine handles a separate but related concern for owners working through a rebuild decision tree.

Updated April 29, 2026 by Matthew Hart. AxleWise covers automotive maintenance, repair, and modification for owners who would rather understand the math than hand a shop a blank check.