LS Engine Bore and Stroke Chart(For All Models)

Understanding bore (cylinder diameter) and stroke (piston travel distance) is essential for engine identification, builds, or modifications. These measurements directly affect displacement, torque, horsepower, and engine characteristics.

Below is a comprehensive bore and stroke chart for the LS engine family, including most major factory variants.

LS Engine Bore and Stroke Chart

Engine (RPO / Name)	Displacement	Bore (in)	Stroke (in)	Displacement (CID)
LR4 (4.8L)	4.8 L	3.780	3.268	293 ci
LM7 (5.3L)	5.3 L	3.780	3.622	325 ci
L59 (5.3L)	5.3 L	3.780	3.622	325 ci
LM4 (5.3L)	5.3 L	3.780	3.622	325 ci
L33 (5.3L)	5.3 L	3.780	3.622	325 ci
LS1 (5.7L)	5.7 L	3.898	3.622	346 ci
LS6 (5.7L)	5.7 L	3.898	3.622	346 ci
LQ4 (6.0L)	6.0 L	4.000	3.622	364 ci
LQ9 (6.0L)	6.0 L	4.000	3.622	364 ci
LS2 (6.0L)	6.0 L	4.000	3.622	364 ci
L76 (6.0L)	6.0 L	4.000	3.622	364 ci
L92 (6.2L)	6.2 L	4.065	3.622	376 ci
LS3 (6.2L)	6.2 L	4.065	3.622	376 ci
L99 (6.2L)	6.2 L	4.065	3.622	376 ci
LSA (6.2L supercharged)	6.2 L	4.065	3.622	376 ci
LS9 (6.2L supercharged)	6.2 L	4.065	3.622	376 ci
LS7 (7.0L)	7.0 L	4.125	4.000	427 ci
L29 (6.0L Truck)	6.0 L	4.000	3.622	364 ci
L33 (5.3L Truck)	5.3 L	3.780	3.622	325 ci
L92 (6.2L Performance)	6.2 L	4.065	3.622	376 ci
LFA (6.2L Performance)	6.2 L	4.065	3.622	376 ci
LZ1 (6.0L Performance)	6.0 L	4.000	3.622	364 ci
LS4 (5.3L FWD)	5.3 L	3.780	3.622	325 ci

Understanding Bore and Stroke

Bore is the diameter of each cylinder. A larger bore allows for larger valves and better airflow, improving high-RPM power.

Stroke is the distance the piston travels from top to bottom. A longer stroke produces more torque at lower RPMs, while a shorter stroke allows higher engine speeds and better peak horsepower.

In LS engines, combinations of bore and stroke define engine character:

LS3/LS9/LSA: Large bore, moderate stroke → high-revving, horsepower-focused.
LS7: Large bore, long stroke → high torque and displacement, strong performance throughout the RPM range.
Truck engines (LM7, LQ4, LQ9): Moderate bore, longer stroke → torque-focused for towing and hauling.

Why Bore and Stroke Matter for Builders

1. Engine Identification

Measuring bore and stroke helps identify an unknown LS engine. For example:

3.780” bore x 3.622” stroke = 5.3L engine (LM7, L59, LM4)
4.065” bore x 3.622” stroke = 6.2L engine (LS3, L92, LSA)
4.125” bore x 4.000” stroke = 7.0L LS7

2. Performance Builds

Bore and stroke determine which aftermarket pistons, rods, and cranks are compatible for stroker builds. A longer stroke increases displacement, boosting torque and power potential.

3. Head and Intake Selection

Bore size affects cylinder head compatibility. LS1/LS6 heads fit 3.898” bore blocks, LS3/LSA heads fit 4.065” bore blocks, and LS7 heads are specific to 4.125” bore.

4. Swap Planning

When swapping LS engines into other vehicles, knowing bore and stroke helps predict performance characteristics and engine size constraints in the chassis.

FAQs

What is the bore size of a 5.3 LS engine?

The 5.3 LS engine, including versions like the LM7, L59, LM4, and L33, has a bore size of 3.780 inches. The stroke is 3.622 inches, giving a total displacement of approximately 325 cubic inches. This bore and stroke combination is common across both truck and SUV 5.3 LS engines.

What is the difference between a 5.3 LS and a 5.7 LS?

The main differences are displacement, bore, and stroke:

5.3 LS: 3.780” bore, 3.622” stroke, 325 ci. Often used in trucks and SUVs.
5.7 LS (LS1/LS6): 3.898” bore, 3.622” stroke, 346 ci. Designed for higher-performance applications like Corvettes and sports cars.
The 5.7 LS has a slightly larger bore, which allows bigger valves and more airflow for higher horsepower potential.

What is the bore size of the LS main?

If you mean the main LS block family, bore sizes vary by engine:

4.8–5.3L truck LS engines: 3.780”
5.7L LS1/LS6: 3.898”
6.0L LS2/LQ4: 4.000”
6.2L LS3/L92/LSA: 4.065”
7.0L LS7: 4.125”
The bore depends on the exact RPO code, but all LS blocks share the same general architecture for compatibility.

How far can you bore a 5.7 LS?

The 5.7 LS block (LS1/LS6) can typically be bored up to 0.030–0.040 inches over stock safely with standard aftermarket pistons. Going beyond this requires careful consideration of cylinder wall thickness to avoid compromising block strength. Some high-performance builders push it slightly further with reinforcing techniques.

What’s the difference between a 5.3 Vortec and 5.3 LS?

The 5.3 Vortec refers to truck and SUV engines, usually with older Vortec heads designed for torque and durability.

5.3 Vortec: Often LM7, L59, or LM4. Optimized for towing and low-end torque.
5.3 LS: Refers to the same basic architecture but sometimes includes later performance upgrades like Active Fuel Management (AFM) or different intake manifolds.
The main difference is application and component tuning, not fundamental block design.

Can a 5.3 be stroked to 383?

Yes, a 5.3 LS can be stroked to 383 cubic inches using aftermarket stroker crankshafts, rods, and pistons. This typically involves:

Increasing stroke from 3.622” to approximately 3.750–3.900”
Using high-performance pistons matched to the new stroke.
Ensuring proper rod-to-stroke ratios and piston deck height

This is a popular upgrade for 5.3 LS engines to increase torque and horsepower while keeping a durable small-block foundation.

Final words

The LS engine family offers incredible flexibility for builds, swaps, and performance tuning. The bore and stroke chart provides essential information for engine identification, component selection, and performance planning.

Understanding the relationship between bore, stroke, and displacement is crucial for any LS enthusiast or engine builder. With this chart, you can confidently identify engines, plan modifications, and select the correct components to achieve your performance goals.