-
Fitment Advice
Unsure if it's the correct part? Call us to confirm
-
In-House Experts
35 years of carburettor experience
-
Genuine Parts
Manufacturer Warranty
-
Australia-wide Delivery
Free shipping on most parts*
- Direct replacement vacuum secondary diaphragm for Holley Six Pack and Tri-power outer carburettors
- Fits both front and rear outboard carburettors on Mopar 440 and 340 engines
- Also suits GM Chevrolet Tri-power systems including Corvette applications
This vacuum secondary diaphragm is designed for the outboard carburettors used in Holley Tri-power and Six Pack systems. On these 3x2 arrangements, the centre carburettor handles primary running while the front and rear units operate as vacuum-controlled secondaries, opening progressively under load. A faulty diaphragm is one of the most common causes of poor Six Pack performance, hesitation, or failure of the outer carburettors to engage. This replacement unit restores proper actuation on both the front and rear carburettors and is suitable for Mopar Six Pack engines as well as GM Chevrolet Tri-power applications including late 1960s Corvettes. It matches all known Holley outboard carburettor list numbers that use this style of vacuum pod.
Specifications
- Product: Holley Tri-Power / Six Pack Secondary Diaphragm
- Application: Outboard (front and rear) vacuum-operated carburettors
- Vehicle Fitment: Mopar 440 and 340, GM Chevrolet Tri-power including Corvette
- Carburettor Operation: Vacuum secondary
- Compatible Holley List Numbers: R3659, R4365-1, R4382-1, R4383-1, R4393-2, R4394-2, R4671, R4672, R4789, R4790
- Fuel Type: Petrol (gasoline)
Inclusions
- Replacement vacuum secondary diaphragm
- Correct sealing lip for Holley outboard pods
Shipping
We ship Australia-wide via Australia Post, with tracked shipping starting from $10.95. Orders are usually dispatched within 24–48 hours, with most deliveries arriving in 2–3 business days. Rural and remote areas may take up to 5 business days.
International shipping is available, with rates calculated at checkout. Local pickup is available from Echuca, VIC — please call ahead on 03 9989 9921 before visiting.
Returns
Returns and exchanges may be accepted within 30 days of receiving your order, provided items are in saleable condition, include original packaging and proof of purchase. Returns are assessed case by case.
Change-of-mind returns, incorrectly ordered items, clearance items and products damaged through misuse or wear and tear are not returnable. Please contact us before sending back any item, especially for warranty claims.