Horsepower vs Torque: What Is the Difference?
Torque is the twisting force an engine applies to its crankshaft, measured in pound-feet (lb-ft). Horsepower is the rate at which the engine does that work: horsepower = torque x RPM / 5,252. Torque tells you how hard the engine pulls at a given engine speed. Horsepower combines that pull with how fast the engine is turning, which is why a high-revving engine can make far more horsepower than torque, and a long-stroke engine can make as much torque as horsepower or more. Neither number is “better”: they are two ways of describing the same output.
What is torque?
Torque is a turning force: a force applied at a distance from a pivot. One pound-foot is one pound of force on a lever one foot long. In an engine, combustion pressure pushes the piston down, and the connecting rod and crankshaft turn that push into torque at the crank. Displacement, cylinder pressure and stroke length all raise torque, which is why big-displacement and stroker engines are known for it.
In a vehicle, torque is the pull you feel when you press the throttle at a given engine speed. The transmission and axle gears then multiply it before it reaches the wheels.
What is horsepower?
Horsepower measures power, meaning work done per unit of time. James Watt defined one horsepower as 33,000 foot-pounds of work per minute. An engine that makes the same torque at twice the RPM does twice as much work per minute, so it makes twice the horsepower.
The horsepower formula
Horsepower = torque (lb-ft) x RPM / 5,252. Turned around, torque = horsepower x 5,252 / RPM.
- An engine making 400 lb-ft at 4,000 rpm is producing about 305 HP at that moment (400 x 4,000 / 5,252).
- Ford Performance rates the 5.2L Aluminator XS at 580 HP at 7,800 rpm. At that speed it is making about 391 lb-ft (580 x 5,252 / 7,800), less than its 445 lb-ft peak, which comes lower in the rev range.
The constant 5,252 comes from the units: 33,000 divided by 2π, because one revolution is 2π radians. It also means that the horsepower and torque curves of any engine cross at 5,252 rpm when they are drawn on the same scale. Below that speed the torque figure is the larger number; above it the horsepower figure is.
Horsepower vs torque: which matters more?
- Towing, hauling and everyday driving: torque at low and middle RPM matters most, because that is where the engine spends its time. A broad torque curve feels strong without revving.
- Acceleration at speed and top speed: horsepower decides how quickly a vehicle keeps gaining speed at higher RPM and what top speed it can reach, because gearing lets the engine trade RPM for torque at the wheels.
- Gearing ties the two together: an engine that makes its power at high RPM can still accelerate hard with numerically higher gears, and a torquey engine can use taller gears.
In practice the shape of the curves matters more than either peak. An engine with a wide, flat torque curve is easier and faster to drive on the street than one with a higher but narrower peak.
Torque curves and the powerband
A peak figure is a single point. The curve shows how the engine behaves everywhere else. When you compare engines, look at where the peaks occur, how wide the usable band is and how high the engine is meant to rev. A peak horsepower figure reached just below the rev limit helps less on the street than strong torque from just above idle.
Spec sheets give clues even without a dyno chart. GM lists a maximum recommended 6,800 rpm for its 6.0L LS364/450 and 6,600 rpm for the LSX 376-B15, and specifies premium pump fuel for the LS364/450 but regular pump fuel for the LSX 376-B15. Compression ratio, camshaft and fuel all shape where an engine makes its power.
Horsepower and torque of real crate engines
These ratings come from each engine’s own specification table, with the price on our site. The two Ford strokers, with long strokes for their bore size, make as much torque as horsepower or more, while the high-revving Aluminator XS makes 135 HP more than its torque figure.
| Engine | Displacement | Horsepower | Torque | Price |
|---|---|---|---|---|
| BluePrint SBF 302 EFI (BP302CTFK) | 302 ci | 361 HP | 334 lb-ft | $10,099 |
| BluePrint SBF 347 stroker EFI (BP3479CTF) | 347 ci | 415 HP | 415 lb-ft | $8,999 |
| BluePrint SBF 408 stroker (BPF4089CTC) | 408 ci | 450 HP | 470 lb-ft | $8,749 |
| BluePrint SBC 400 (BP4002CT1) | 400 ci | 500 HP | 510 lb-ft | $7,349 |
| GM Performance 6.0L LS364/450 | 364 ci | 452 HP | 441 lb-ft | $7,285 |
| BluePrint 426 Gen III Hemi EFI (PS426CTF) | 426 ci | 610 HP | 525 lb-ft | $16,899 |
| Ford Performance Aluminator XS 5.2L | 317 ci | 580 HP | 445 lb-ft | $27,100 |
Prices change, so check each product page for the current price. To see how stroke length changes torque, read what a stroker engine is and the 347 stroker guide.
Crank vs wheel horsepower, and gross vs net
- Crank (flywheel) horsepower is measured at the engine, usually on an engine dyno. Crate engine ratings are engine ratings; BluePrint’s specification tables mark many of its engines as dyno tested.
- Wheel horsepower is measured at the driven wheels on a chassis dyno. It is always lower, because the transmission, driveshaft and axle absorb some power, and how much depends on the drivetrain and the dyno.
- Gross vs net horsepower: before 1972, US carmakers quoted SAE gross ratings, measured without accessories and with minimal intake and exhaust restriction. SAE net ratings, used since then, measure the engine as installed, so older gross figures look high next to modern ones. The original 426 Hemi’s 425 HP, for example, was a gross rating; see the 426 Hemi engine guide.
When you compare a crate engine with a factory engine or a dyno sheet, make sure both figures were measured the same way.
How to read an engine spec sheet
Peak horsepower is the number that gets advertised, but on its own it rarely tells you how an engine will suit your vehicle. Before you buy, check:
- Torque and where it peaks, not only peak horsepower.
- Displacement, bore and stroke, which set the engine’s character.
- Compression ratio and fuel: higher compression usually calls for higher-octane fuel.
- Camshaft and maximum recommended RPM, which decide where the power is made.
- What the rating includes: engine or wheel, gross or net, and with which intake, exhaust and accessories.
Comparing whole engine families? See big block vs small block, the LS3 engine guide and crate engine prices, or browse all crate engines.
Frequently asked questions
Is horsepower or torque better for towing?
Torque at low and middle RPM matters most for towing, because it decides how strongly the engine pulls a heavy load without revving. Horsepower still decides how fast you can climb a grade with the load, so good towing engines make strong torque across a wide RPM range.
How do you calculate horsepower from torque?
Multiply torque in lb-ft by RPM and divide by 5,252. For example, 450 lb-ft at 5,000 rpm is about 428 HP.
Why do horsepower and torque cross at 5,252 rpm?
Because 5,252 is the constant in the formula. At 5,252 rpm, horsepower = torque x 5,252 / 5,252, so the two numbers are equal.
Is wheel horsepower lower than crank horsepower?
Yes. Wheel horsepower is measured after the transmission and driveline, which absorb some power, so it is always lower than the engine’s crank rating.
What does torque do in a car?
Torque is the turning force that, multiplied by the gears, drives the wheels. More torque at a given RPM means stronger acceleration at that engine speed.
Is 400 lb-ft of torque good?
For a car or light truck, yes: 400 lb-ft is strong street torque. GM rates its 6.2L LS3 crate engine at 425 lb-ft, while big blocks and strokers make more and heavy-duty diesels far more. Whether it is enough depends on the vehicle’s weight and use, and where the torque peak comes and how broad the curve is matter as much as the number.
Related: how to break in a new engine, gas vs diesel engines, 383 stroker engine, what is a crate engine?, compression ratio, lobe separation angle, liters to cubic inches, all guides.
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