How to Choose the Right Granatelli Throttle Body Size for LS, LT and HEMI Builds

A larger throttle body can increase the airflow capacity at the entrance to the intake manifold, but bigger is not automatically better on every engine.

Granatelli Motor Sports offers high-flow electronic drive-by-wire throttle bodies for GM LS, Gen V LT and HEMI applications, from 95mm up to 120mm. The right choice depends on the complete intake system. This guide walks through how to match the bore to your manifold, which part numbers fit which engines, and what trips people up on install day.

What the Throttle Body Actually Does

The throttle body controls how much air enters the intake manifold. At wide-open throttle, the bore becomes part of the total airflow path, along with the air inlet, manifold opening, cylinder heads and engine displacement.

If another component is already the main restriction, installing a much larger throttle body may provide little benefit until the rest of the combination is matched. That is why we do not quote a fixed horsepower number for any throttle body. The gain depends on whether the throttle body was the restriction in your combination.

Granatelli Throttle Body Size Chart: LS, LT and HEMI

Every unit below is a complete electronic drive-by-wire assembly, so nothing moves over from your factory throttle body. Prices and boost ratings are from the product pages as of October 2026.

Choosing an LS Throttle Body

Start with the manifold. On a stock-style LS3 intake, or a boosted 6.2L, the 103mm units are the usual answer. The billet GMTBLS3 family lists LS1, LS2, LS3, LS6, LS7, LS9, LSA, LSX, LQ4 and LQ9 when the correct 6-pin drive-by-wire setup is used. The black GMTBLS3B is CNC-machined from 6061-T6 billet, uses a factory-style GM 6-pin connection, and is listed for both draw-through and blow-through boost up to 35 psi. The cast GMTBLS3M costs less, includes an adapter, and carries the same 35 psi rating.

If the engine needs more airflow and the manifold can take it, the 108mm GMTBLS108 and 112mm GMTBLS112B also list LS3. The 112mm has a reinforced motor and throttle-blade assembly, and some manifolds need an adapter for it. Granatelli also sells the GMTBLS112SPC ($235.66), which is a billet spacer for the 112mm LS unit, not a throttle body.

On a Granatelli ZILLA manifold, the inlet decides it for you: the ZILLA 105mm takes the GMTBLS105 or GMTBLS105B, and the ZILLA 120mm takes the GMTBLS120. Trailblazer SS owners should call before ordering any LS unit, because that application needs specific calibration.

Choosing a Gen V LT Throttle Body

High-output LT1, LT4 and LT5 combinations can demand substantially more inlet area. The 103mm GMTBLT4 and GMTBLT4B and the 112mm GMTBLT112 and GMTBLT112B are listed for Gen V LT1, LT4 and LT5 engines with the factory-style GM 6-pin connector. The 112mm units use a high-torque motor and are intended for serious naturally aspirated and forced-induction builds where the intake manifold and inlet tract can use the additional area.

Running a 103mm on a stock LT1 or LT4 intake takes the GMTBLTSPC adapter spacer plate ($235.66). The gasket and mounting hardware are not included with the plate. The 95mm GMTBLT95B is listed for the LT1 and select Gen V 5.3L and 6.2L applications; fit varies by model year and intake, so call with your vehicle details first.

Choosing a HEMI Throttle Body

For compatible Dodge, Chrysler, Jeep and Ram HEMI applications, Granatelli offers the 95mm HLC line in billet (GMTBHLC, black GMTBHLCB) and black cast (GMTBHLCM). They fit the 5.7L, 6.1L and 6.4L / 392 drive-by-wire HEMI. Check the exact listing: the GMTBHLCB lists 5.7L and 6.4L / 392 only.

Two fitment points catch people. First, vehicles with the factory E-Torque system cannot run these 95mm units because there is not enough physical clearance. Second, 2005 to 2010 HEMI vehicles need the Granatelli adapter harness, while the GMTBHLCB page states no adapter or harness is needed on compatible 2013 and newer applications.

The 95mm HLC units do not fit the supercharged 6.2L Hellcat, Hellcat Redeye or Demon. Hellcat and Trackhawk owners need the SRT series: 105mm GMTBSRTH / GMTBSRTHB ($811.72) or 108mm GMTBSRT108 / GMTBSRT108B ($847.88). The Hellcat and Redeye use the same throttle body.

Match the Throttle Body to the Intake Manifold

• Confirm the manifold opening is large enough for the throttle body
• Verify bolt pattern and electronic connector
• Check hood and accessory clearance
• Confirm whether an adapter is required
• Check that your intake tube and coupler fit the new inlet
• Plan tuning before installation on heavily modified combinations

A bigger throttle body often has a bigger inlet, so the factory intake tube may not fit. Measure the throttle body inlet and compare it to your coupler. If you change couplers, size the clamp to the installed coupler outside diameter, as covered in our guide on how to measure for the correct Granatelli billet hose clamp size.

Common Mistakes

• Ordering by millimeters alone. Bore size is one factor. Mounting, electronics, manifold opening and calibration must also match.
• Assuming the biggest is best on a stock engine. Choose a size that fits the intake and the engine's airflow needs without creating clearance or calibration problems.
• Forcing a connector. Same pin count does not mean the same pinout. Never force a plug or assume a lookalike adapter is correct.
• Ordering a 95mm HLC for a Hellcat. Different engine, different throttle body.
• Hanging heavy intake piping off the throttle body. Support it independently.

Will You Need a Tune?

Plan on it. Every Granatelli throttle body product page says a tune may be required for proper electronic throttle operation, idle quality, drivability and optimum performance, especially when moving to a much larger bore or installing the throttle body on a modified or forced-induction engine. The HEMI pages add that a tune helps prevent check-engine lights. Some vehicles also need a throttle relearn after the swap.

The Bottom Line

Choose the throttle body as part of the complete airflow system, not by bore size alone. When the manifold, inlet path, calibration and engine combination are matched, a Granatelli high-flow throttle body can remove an unnecessary restriction while retaining modern drive-by-wire control.

For every fitment detail by part number, see the Throttle Body FAQ, or the Intake Manifold FAQ for manifold questions. Still unsure? Call 1-805-486-6644, Monday to Friday, 8am to 5pm Pacific, with your year, make, model, engine, intake manifold and a photo of your connector.

Throttle Body Sizing FAQ

Do I need a tune with a bigger throttle body?

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

Will a bigger throttle body always add horsepower?

No. A larger throttle body only helps when it removes an airflow restriction in the overall combination. Intake, cylinder heads, induction and tuning all matter, so Granatelli Motor Sports does not quote a fixed horsepower number.

What size throttle body should I run on an LS3?

Match the throttle body to your intake opening, bolt pattern, 6-pin connector and boost level. On a stock-style or boosted LS3 intake, the 103mm cast GMTBLS3M or billet GMTBLS3, GMTBLS3B and GMTBLS3P are listed for LS3. The 108mm GMTBLS108 and 112mm GMTBLS112B also list LS3 for engines that need more airflow.

Can I run a 103mm throttle body on a stock LT1 or LT4 intake?

Yes, with the GMTBLTSPC billet adapter spacer plate. It mounts the GMTBLT4 or GMTBLT4B 103mm throttle body to a stock GM LT1 or LT4 intake. The gasket and mounting hardware are not included, and a tune may be required.

Does the 95mm HEMI throttle body fit a Hellcat?

No. The 95mm GMTBHLC, GMTBHLCB and GMTBHLCM are for the 5.7L, 6.1L and 6.4L HEMI and do not fit the Hellcat, Hellcat Redeye or Demon. Hellcat and Trackhawk owners need the 105mm or 108mm SRT-series throttle bodies.

Will the 95mm HEMI throttle body fit a vehicle with E-Torque?

No. There is not enough physical clearance on vehicles with the factory E-Torque system. If your vehicle has E-Torque, do not order the 95mm HEMI units.