Whipple 12-Rib Supercharger Pulleys for Mercury Racing 850/1025/1075/1200 SCI

Whipple 12-Rib Supercharger Pulleys
Mercury Racing 850/1025/1075/1200 SCI

These Whipple 12-rib supercharger pulleys are designed for compatible Mercury Racing 850/1025/1075/1200 SCI applications and related Whipple marine supercharger belt-drive setups. Each pulley is machined from 6061-T6 billet aluminum and anodized for wear resistance and environmental protection in demanding marine-use conditions.

The pulley design includes lightweight pocketing to help reduce rotating mass, a guarded outer profile to help reduce unwanted belt wandering during hard running, and engraved running diameter identification for easier service and setup verification. Pulley dimensions are based on the running diameter.

This product is available in multiple running diameters: 4.05", 4.45", 4.65", and 4.85". Standard finish is hard coat clear anodized.

Stock pulley reference:

• Mercury Racing 1025/1075/1200 SCI: 4.05" stock diameter
• Mercury Racing 850 SCI: 4.73" stock diameter; use 4.65" for replacement

General pulley sizing note: As a general rule of thumb, every 0.125" pulley change is approximately 0.75 PSI of boost change, increasing or decreasing depending on pulley direction and the full drive combination. Actual boost change can vary based on engine setup, supercharger configuration, belt system, operating conditions, PCM control strategy, calibration, and supporting hardware. On stock PCM-controlled applications, pulley changes may not change boost levels without the proper supporting calibration and setup.

Application note: Whipple supercharger pulleys are application-specific. Verify pulley diameter, rib count, belt system, calibration requirements, and application before ordering. Do not order this pulley for a different application unless compatibility has been confirmed.

Returns note: There are no returns or exchanges for used pulleys.

Key Features

• 12-rib supercharger pulley
• Designed for compatible Mercury Racing 850/1025/1075/1200 SCI applications
• Billet 6061-T6 aluminum construction
• Hard coat clear anodized finish
• Available in 4.05", 4.45", 4.65", and 4.85" running diameters
• Engraved running diameter identification
• Lightweight pocketed design helps reduce rotating mass
• Guarded profile helps reduce belt wandering during hard running