M122 Supercharger Service — Porting, Rebuild & Snout Bearing for Shelby GT500 and Ford GT
FAS Motorsports ports, rebuilds, and performs snout bearing service on Eaton M122 superchargers for Shelby GT500 and Ford GT applications. We receive units nationwide from our facility in Punta Gorda, FL.
Vehicle Applications
- 2007–2012 Ford Shelby GT500 (5.4L 4V) — 500–550 crank hp stock
- 2013–2014 Ford Shelby GT500 (5.8L "Trinity") — 662 crank hp stock
- 2005–2006 Ford GT (5.4L supercharged, mid-engine) — 550 crank hp stock
Supercharger Specifications
- Type: Roots-type positive-displacement
- Displacement: 122 cubic inches / approximately 2.0 liters
- vs. M112: Larger displacement, larger inlet and discharge port geometry, higher flow capacity at equivalent RPM
- Bypass valve: Integrated on GT500 application — inspected and serviced on every rebuild
- Factory output (5.8L Trinity GT500): 662 crank hp / approximately 560–590 whp
Services
- Snout porting — inlet throat opening, casting flash removal, port transition shaping. Larger port geometry than the M112 but factory restrictions still present.
- Full inlet porting — snout plus discharge port. Standard before pulley reduction on GT500 builds targeting 700+ rwhp.
- Snout bearing replacement — standard on every rebuild.
- Front seal replacement — paired with bearing service.
- Bypass valve inspection and service — GT500 application. A stuck valve causes boost leaks and inconsistent power delivery.
- Full rebuild — complete teardown, rotor clearance check, all bearing and seal service, bypass valve service, port work, reassembly to spec, rotation verification before shipping.
Common Failure Points
Snout bearing wear — same failure mode as the M112; RPM-tracking whine that worsens under boost is the indicator.
Bypass valve sticking — GT500 integrated bypass. A stuck valve produces boost leaks and inconsistent power delivery under load.
Rotor tip wear on high-cycle units — more common on track cars; reduces volumetric efficiency. Identified during teardown inspection.
Inlet restriction — factory casting limits airflow above the stock power level. Porting is the primary solution.
Shelby GT500 Build Path
The 2013–2014 GT500 5.8L Trinity already has forged internals, aggressive cam profiles, and a capable fuel system from the factory — the M122 has porting headroom the rest of the engine can absorb. Typical build sequence:
- M122 port and rebuild — do this while the engine is accessible
- Pulley reduction to increase boost
- Tune (mandatory after any pulley change)
- Supporting fuel upgrades for builds targeting 700+ rwhp on E85
The ported and rebuilt M122 with a pulley change and tune is a well-documented path to 700+ rwhp on the Trinity motor with proper supporting mods. FAS handles the blower work.
Ford GT Notes
The Ford GT uses a mid-engine M122 variant with a different inlet geometry and dry-sump oiling system from the Mustang application. We have rebuilt Ford GT M122 units and understand the platform differences. Contact us directly before shipping — we will confirm scope and process for your VIN.
How to Send Your Unit
Remove the supercharger and ship to FAS Motorsports in Punta Gorda, FL. We inspect on arrival and contact you before proceeding. Pricing and turnaround time are confirmed at intake.
Contact us to arrange service.
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