This vacuum secondary housing cover lets you swap the secondary diaphragm spring for quicker tuning changes without disturbing the diaphragm itself.
Specifications:
- Brand: Holley
- Category: Air and Fuel Delivery
- Color: Black
- Material: Plastic
- Part Type: Carburetor Accelerator Pump Cover
- Product Type: Vacuum Secondary Cover
- Sub Category: Carburetion
- Part Number: 20-59
Designed to expedite changing of the vacuum secondary spring for on-track or dyno tuning sessions.
FAQ
What does this cover let me do?
It allows the secondary diaphragm spring to be changed without disturbing the diaphragm, speeding up tuning adjustments.
What is it made of?
The cover is molded from black plastic.
Will this fit any Holley carburetor?
It is designed as a quick-change vacuum secondary housing cover for Holley carburetors using this style diaphragm housing; confirm fitment against your carburetor's existing cover before ordering.
What is the part number?
Holley part number 20-59.

