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GFB Whistling Trumpet (only for Stealth FX and WRX Hybrid)

The 5701 can be used in place of the standard trumpet on GFB valves (Part numbers T9003 & T9503), and will make a whistling sound. However, it is necessary to run the valve so that all (or most) of...

GFB Whistling Trumpet (suits all valves)

The 5702 can be used in place of the standard trumpet on all GFB valves, and will make the whistling sound more readily than the 5701 (high boost and RPM is required to get the whistle from a 5701),...