Holley Chrome Vacuum Secondary Diaphragm Housing and Cover 34-503 Chassis Helps improve engine efficiency with

Helps improve engine efficiency with better air flow

1/2" NPT x 6AN male adapters

Large surface area pulls more air at low speeds

Hardware kit with hose barb fittings and hose clamps included

Suits Big Block Chev 396-402-427-454

Holley Chrome Vacuum Secondary Diaphragm Housing and Cover 34-503 Chassis Helps improve engine efficiency withGenuine Holley Vacuum Secondary Diaphragm Housings and Covers are designed to replace your existing cover without any modifications. They are made of die cast aluminium and are chrome plated for durability. Sold individually, discontinued by Holley making these rare and hard to find. Holley Part No. 34 503 If carburetor is equipped with a black plastic cover then you must also purchase a special choke cable clamp kit, Holley Part No. 45 456, if you