LS3 Intake Manifold Mod (Ported Rod Mod or Rod Mod Only)

(105 customer reviews)


Gwatney Performance

Current Estimated Lead Time: 6-8 Weeks

GPI – LS3 Intake Manifold Mod – Best Performing and Value Intake Manifold for your LS3!

Rod Mod Only
During the “Rod-Mod” process, we take the LS3 intake manifold and install radius bars lengthwise in the plenum. Through research and development, we have learned that air does not like moving over sharp turns – it creates unwanted turbulence. The radius bars we install are carefully selected, measured, and cut to a specific length and assists in transitioning air from the main plenum into the runners. This helps to maintain proper airflow and velocity. In addition, we minimally grind and smooth the area inside the runners where the injector boss protrudes into the runner, ensuring minimal disturbance to airflow from the injector boss. The Rod-Mod is ideal for forced induction applications, as well as nitrous applications as it does not compromise the structural integrity of the manifold during high-pressure events.

Est Gains: 6 HP for bolt-ons & 12 HP for cammed setups.

Ported Rod Mod (Popular)
During the “Ported-Rod-Mod” process, we begin by removing the vertical stands that run inside the manifold plenum. These stands are large and very obstructive to flowing air. Once removed, we adequately seal the plenum floor back up, and slightly grind/smooth the floor of the plenum. Next, we port the air inlet section of the manifold along with grinding/smoothing the injector bosses protruding into the runners. Once all porting/grinding work is completed, we then install the same carefully selected radius bars that we use in the Rod-Mod. Again, these bars greatly assist with transitioning air from the plenum into the runners, maintaining maximum airflow and velocity. The Porting-Mod is ideal for naturally aspirated applications and performs at its best in a cammed setup. At no point do we recommend the Porting-Mod for forced induction or nitrous applications, as the stand removal does lessen the structural strength of the manifold.

Est Gain: We don’t see significantly more peak power over Rod Mod (+1 or 2 HP), but we see it across the entire powerband and the midrange torque increase is worth doing the Porting Mod if you can.

SKU: GPI-LS3-MANIFOLD-MOD Categories: , , Brand: