Cast vs. Billet Granatelli Throttle Bodies: Which One Fits Your Build?

Granatelli offers both cast and billet performance throttle bodies because not every build has the same priorities. Some customers want maximum billet construction and finish quality, while others want a high-flow upgrade at a lower cost.

The important point is that cast versus billet does not automatically tell you how much horsepower the throttle body will support. Bore size, motor design, boost sealing, calibration and the rest of the intake system matter too. Here is how the two compare, part number by part number.

Cast vs. Billet: Side-by-Side Comparison

The choice only exists in two places: the GM LS 103mm and the 95mm HEMI. Every other Granatelli throttle body is billet. Specs and prices from the product listings, as of October 2026.

The cast units save $235.66 over the billet versions at the same bore size. All of them are complete drive-by-wire assemblies, and the product pages for GMTBLS3M, GMTBLS3B, GMTBLS3P, GMTBHLC, GMTBHLCB and GMTBHLCM state Made in the USA.

What You Get with a Billet Throttle Body

Billet models such as the Granatelli 103mm LS and 95mm HEMI throttle bodies are CNC-machined from billet aluminum, 6061-T6 on most models. This provides precise dimensional control, a premium appearance and a strong housing for serious street and performance combinations.

Billet also gives you finish choices. The LS 103mm comes in natural (GMTBLS3), black (GMTBLS3B) and polished (GMTBLS3P), and the HEMI 95mm in natural (GMTBHLC) and black (GMTBHLCB). The polished GMTBLS3P adds a high-torque servo motor and is rated to 35 psi. Billet construction is especially attractive on custom engine bays where the throttle body is a visible part of the build.

What You Get with a Cast Throttle Body

Granatelli also offers cast-aluminum throttle bodies with precision-machined critical surfaces. A cast body can provide the required airflow and electronic throttle control without the cost of machining the entire housing from billet.

For example, Granatelli's 103mm cast LS throttle body, the GMTBLS3M, is built for serious performance use and is listed for high-boost applications up to 35 psi, with an electronic motor designed to resist throttle flutter and unwanted blade movement under boost. It uses a factory-style GM 6-pin connector and includes the required adapter for compatible installations. The HEMI GMTBHLCM gets you the same 95mm bore as the billet HEMI units in a black cast housing.

Airflow Is Controlled by More Than Material

The engine does not know whether the throttle body started as a billet or casting. It responds to usable airflow, bore area, blade position and the quality of the complete induction path. A cast 103mm and a billet 103mm have the same bore.

Do not choose based on material alone. Verify bore size, boost rating, manifold compatibility, connector type and tuning needs for the exact part number. Note that engine listings differ: the billet LS 103mm lists a wider range of LS engines, while the cast GMTBLS3M lists LS3, LSA, LSX and boosted 6.2L combinations.

When Billet Makes the Most Sense

• Premium or show-quality engine bays
• Builders who want CNC-machined 6061-T6 construction
• High-end street/strip combinations
• Applications where finish and precision are a priority, including the polished GMTBLS3P
• LS engines outside the cast unit's listing, such as LS1, LS2, LS6, LS7, LS9, LQ4 and LQ9
• Any bore or engine family other than LS 103mm and HEMI 95mm, since those are billet only

When Cast Makes the Most Sense

• Budget-conscious performance builds
• Applications where airflow is the primary goal
• Street and race combinations that do not require a billet appearance
• High-boost LS3, LSA and LSX builds on a budget
• Builders matching a proven cast Granatelli part number to the setup

Fitment Checks That Apply to Both

On the HEMI side, cast or billet makes no difference to these rules. None of the 95mm HLC units fit the supercharged 6.2L Hellcat, Hellcat Redeye or Demon; Hellcat and Trackhawk owners need the 105mm or 108mm SRT-series billet units. None fit vehicles with the factory E-Torque system, because there is not enough clearance. And 2005 to 2010 HEMI vehicles need the Granatelli adapter harness.

On the LS side, verify the connector, manifold bolt pattern, throttle opening and clearance. Trailblazer SS owners should call before ordering, and the polished GMTBLS3P is listed as not compatible with the Trailblazer SS. A larger throttle body can also change the inlet size your intake tube has to meet, so check the coupler fit; our guide on how to measure for the correct Granatelli billet hose clamp size covers sizing the clamp to the installed coupler, and why billet hose clamps matter on boosted builds covers keeping that joint sealed under boost.

Do Not Skip Calibration

Large electronic throttle bodies can require calibration changes. Throttle-area modeling, idle airflow and electronic throttle behavior all need to remain predictable. Every Granatelli throttle body product page says a tune may be required, and the HEMI pages add that it helps prevent check-engine lights. On heavily modified combinations, plan the throttle body and tune together.

The Bottom Line

Cast and billet are two different ways to build a high-flow throttle body; neither choice should be made in isolation. Start with the engine, manifold, bore requirement, boost level and calibration, then choose the Granatelli construction and finish that fit the build.

For more detail by part number, see the Throttle Body FAQ or browse the throttle body collection. Questions? Call 1-805-486-6644, Monday to Friday, 8am to 5pm Pacific. Granatelli throttle bodies carry a 90-day warranty, with optional 1-, 2- or 3-year extended coverage at checkout.

Cast vs. Billet Throttle Body FAQ

Is a billet throttle body better than a cast one?

Not automatically. Billet gives you 6061-T6 CNC-machined construction and more finish choices, while cast costs less at the same bore. Airflow depends on bore size, blade position and the whole intake path, not the housing material.

Which Granatelli throttle bodies are cast?

Two: the GM LS 103mm GMTBLS3M and the HEMI 95mm black GMTBHLCM. Both are $445.13 as of October 2026. Every other Granatelli throttle body is billet.

Can a cast throttle body handle boost?

Yes. The cast LS 103mm GMTBLS3M is rated for up to 35 psi, the same as the billet LS 103mm units. Every Granatelli GM LS and LT throttle body carries a 35 psi rating. Check the exact product page for your part number.

Does the cast 95mm HEMI throttle body fit a Hellcat?

No. The GMTBHLCM, like the billet GMTBHLC and GMTBHLCB, is for the 5.7L, 6.1L and 6.4L HEMI and does not fit the Hellcat, Hellcat Redeye or Demon. Hellcat owners need the 105mm or 108mm SRT-series billet units.

Do I need a tune with a cast or billet throttle body?

Plan on one either way. Every Granatelli throttle body product page says a tune may be required after installation for proper idle quality, drivability and throttle response, especially on modified or boosted engines.