Holley 1904, 1920 Pump Diaphragm Spring 66-435

Holley 1904, 1920 Diaphragm Spring - 66-435

6 Review(s)

Your Price: $3.95

Part Number: 66-435

Availability: In Stock

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Customer Reviews

Holley 1904, 1 barrel accelerator pump diaphragm spring. This is the conical spring that goes behind the pump diaphragm. See #37 in the illustration.

This spring is critical to having a good accelerator pump action. Without it you will get a hesitation when stepping on the gas.

We have these springs custom made here in the US.

1904 Diaphragm Spring

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5.0

Great service , excellent products

Could not believe my luck. Did a search online for accelerator pump spring 1965 Holley 1904 single barrel , rolling my eyes. ! And holy smokes Mikes Carburetor Lists it and stocks it ! I ordered up and in 4 days I had the part , fits perfectly . Thanx very much !

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Reviewed by: Terry from Wasilla Alaska on 6/30/2026

Diaphragm Spring

Quick delivery. Quality product. Appreciate all of the additional information and tips on your website!

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Reviewed by: Carletta N from Iowa on 10/1/2025

Car guy

Received this part shortly after ordering. Rebuilt my carburetor and all is well. Great service. Could not be happier. Thanks so much.

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Reviewed by: Kip Awbrey from Lancaster on 5/4/2021

Customer

Great product, shipped quickly, worked well!

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Reviewed by: Patrick sullivan from Florida on 2/1/2019

Retired

I rebuilt the single barrel Holley carb on my son's old 1965 Dodge Dart. I need to replace the pump spring and Mike's had the part, it shipped fast and fit perfectly. The old girl roared back to life after sitting for ten years and actually run pretty good. Thanks Mike's for great service.

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Reviewed by: Mike Fadden from Ripon,WI on 7/2/2017

Restorationist

Functions Perfectly, Exact Fit. Took my 1920 apart and found this spring missing. Installed this spring and the rebuild kit from this site, and the Slant 6 is running like a dream again!

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Reviewed by: Dan from Des Plaines, IL on 5/15/2016

Holley 1904, 1920 Diaphragm Spring - 66-435

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