What size is a stock LS throttle body?

There isn’t a single universal size for every LS engine—stock throttle body bore sizes vary by model and year. In general, early LS1-era setups used smaller bores, while later LS variants use significantly larger ones. For most modern LS V8s, you’ll encounter sizes in the mid to high range, roughly from the high 50s up to the low 100s millimeters, depending on the specific engine family and configuration.

Stock throttle bodies across the LS family

The following breakdown provides a broad sense of how throttle body bore sizes differ by major LS generations and applications.

• Early LS1-era engines (late 1990s to early 2000s): typically smaller bore sizes in the low-to-mid 50s millimeters.


• Mid-generation LS2/LS6 era (mid-2000s): larger bores that move into the mid-70s to low-90s millimeters, depending on model and application.


• Late-generation LS3 and newer (including many trucks and performance variants starting around 2008): generally around the 78–92 millimeter range, with some high-performance or factory-trimmed setups approaching the upper end of that spectrum.

The exact stock size for any given vehicle should be verified on the throttle body itself or via the GM parts catalog using the vehicle’s VIN and engine code, as there are exceptions based on model year and market.

How to verify your exact size

To confirm the precise bore of your stock LS throttle body, use these steps.

1. Identify your engine family and model year, which determines the likely stock range.


2. Physically measure the bore with calipers by locating the throttle body opening on the inlet side.


3. Look up the GM part number stamped on or near the throttle body or consult the factory service manual/GM parts catalog for your VIN to confirm the official bore size.


4. Cross-check online parts databases or forums for model-specific documentation to validate the factory size.

Once you’ve confirmed the bore size, you’ll be better prepared to compare aftermarket options or to assess how a tune or intake upgrade might interact with the stock geometry.

Why throttle body size matters

Throttle body size influences how much air can flow at a given throttle opening. A larger bore can support more air and potential power, but only when the rest of the induction system (manifold, cam, intake, and tuning) is matched to it. Using a size that’s too large without corresponding supporting modifications can degrade low-end response and idle stability, while a size that’s too small can limit top-end power on higher-performance builds.

Summary

In short, there isn’t a single “stock LS throttle body size.” Expect a range from the low 50s millimeters on older LS1 configurations up to the 90–92 mm zone on many later LS variants, with common modern applications often landing in the 78–92 mm band. Determine the exact size by checking the throttle body’s bore, the engine’s model/year, or the GM parts catalog using your VIN, and plan upgrades accordingly to ensure proper fit and tuning.

What size is the OEM ls3 throttle body?

The stock LS3 throttle body is a 90mm size, featuring a 4-bolt mounting pattern, a gold throttle blade, and an electronic, drive-by-wire system. Its intake manifold opening is also 92mm, meaning that a 92mm throttle body is a factory-matched size, but a 102mm throttle body with an adapter can be used for more power, especially on modified engines.
 
This video explains the LS throttle bodies and when to upgrade: 1mAuto GuildYouTube · Dec 28, 2024

• Size: 90mm
• Mounting: 4-bolt
• Blade: Gold-colored
• Type: Electronic, drive-by-wire 

Upgrading your throttle body 

• A larger, aftermarket throttle body, like a 102mm or 103mm, may provide more airflow and power, especially on modified engines with a new intake manifold. 
• To use a larger throttle body with a stock LS3 intake manifold, you will need an adapter that tapers the opening from 92mm to the larger size. 
• For the best performance gains, the throttle body size should match the intake manifold's capacity. A larger throttle body on a stock manifold may offer little to no benefit. 

This video discusses the effectiveness of a larger throttle body: 49sRichard HoldenerYouTube · Dec 13, 2019

What size is a LS throttle body?

LS throttle body sizes vary by model, with many earlier engines using smaller, 75-78mm throttle bodies. Newer versions, especially those with four-bolt patterns, are often 90mm (like the LS3) or larger, with aftermarket options available up to 102mm and beyond. The appropriate size depends on the engine's requirements and whether a matched intake manifold is used, as a larger throttle body won't provide benefits without a matching intake opening.
 
Factory LS throttle body sizes

• Early models: The first Corvette (1997) had a 75mm blade in a 78mm casing, while early truck engines typically used 80mm cable-operated throttle bodies. 
• Four-bolt, new style: Many Gen 4 engines like the LS2, LS3, and LS7 use a 90mm throttle body. 
• Gen 4 truck: Some modern truck throttle bodies can be in the 87mm range. 

Aftermarket throttle body sizes

• Aftermarket options: Aftermarket throttle bodies are available in a wide range of sizes, including common options like 92mm, 102mm, 103mm, and 105mm. 
• Matching intake: To gain any benefit from a larger throttle body, it must be matched to an intake manifold with an opening of a similar size. Using a larger throttle body with a restrictive factory intake will not significantly improve performance. 
• Supercharged engines: Supercharged engines often show significant gains with larger throttle bodies because they can take advantage of the increased airflow to create more boost. 

What size throttle body is a 5.3 LS stock?

The stock throttle body size for a 5.3L LS engine is typically 78mm or 76mm for older Gen 3 models, while later Gen 4 models often use an 87mm or 90mm throttle body. The size depends on the specific engine and its year of manufacture, with a transition to drive-by-wire (DBW) systems and larger sizes starting around 2003-2004. 
Older Gen 3 (e.g., LM7)

• Size: 78mm, 3-bolt for early models
• Control: Cable operated 

Newer Gen 4 (e.g., LS2)

• Size: 87mm or 90mm
• Control: Drive-by-wire (DBW)
• Example: The L92 throttle body, an 87mm unit, is used on 6.0L and 6.2L truck engines. 

What this means for you

• If you have an older truck/SUV: You likely have a 78mm or 76mm throttle body, which is a common bottleneck for modified engines. 
• If you have a newer truck/SUV: You likely have an 87mm or 90mm throttle body, which is already larger than many aftermarket options and often sufficient for modified applications. 
• For modifications: If you are modifying your engine, you can upgrade to a larger throttle body like a 90mm or 92mm to see potential performance gains, especially at higher RPMs. You may need an adapter plate to fit it to your stock intake manifold. 

Are all LS throttle bodies the same?

All LS (and LT for that matter) 4 bolt throttle bodies share the same size bolt pattern stock and aftermarket. However, bore restrictions, and oversizing will require you to have a matching throttle body. For instance some 102mm intakes will not seal a 92mm throttle body.