Thread: How to tell Carb model?

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With the square flange family of Holleys, there are 2 models 4150 and 4160.
The 4150 hase a metering block on the secondary side as well as the primary side. Therefore this carburettor is longer.

A 4160 has a metering plate on the secondary side that is covered by the fuel bowl.

Here is an example for a holley list 3310 you may notice that there is a space after this list number and it has a 1 or 2 after it. This suffix number denotes wether it is a 4150 or 4160 model.

So 3310 - x = 750 cfm vacume sec

- 1 = 4150

- 2 = 4160.

Now.... this applies to new carburetors and well looked after original old ones, as you can buy metering block kits to convert your 4160 series carb to a 4150 series.

Vacume secondarys and double pumpers.

This is easy the vacume secondary has a vacume chamber out the side. And no secondary accelerator pump.

The double pumper has a secondary accelerator pump circuit and they are allways a 4150 model carburetor. The secondarys are manually operated by a progresive linkage from the primary throttle shaft.