Ferrari 355 - Bypass Exhaust Valve KitFerrari 355 Exhaust By Pass Valve Kit (Incl. Sealing Rings) This valve has been constructed specifically to address problems previously associated with failure of the OEM unit. The OEM valve typically failed in the 'closed' position, resulting in high exhaust back pressure, which resulted in engine and or header heat damage. The CAPRISTO replacement valve has been redesigned in a different configuration. Should a vacuum and or electrical failure