1950 Willys Truck re-rebuild by 50wllystrk

3 minute(s) of a 620 minute read

Next up we're gonna get to the secondaries side of the Holley again.

Going back to the vacuum operated secondary carb, where we have the vacuum canister attached to the side of the carb. Remembering that this design does not have an accelerator pump. Also knowing that the secondaries do not use a power valve, all that we need is to regulate the amount of fuel being allowed into the intake manifold.

What we are talking about is getting rid of the usage of the whole metering block that we had on the primary side. We've seen this metering block, it had a passage for the accelerater pump shot of fuel to pass through, the power valve screwed into it, the screws that adjust the idle fuel mixture are on the sides of it and the two brass jets are screwed into it also.

The next picture will introduce the metering plate. It is a simplified plate that replaces the block. Remember, it has far less to do.

Block on the left, plate on the right.

Talk about simple.... The block is actually sandwiched between the float bowl and the main center section of the carb. The plate however, is attached directly to the main center section and the float bowl does not touch this plate.

As we can see by the next picture.

In the previous two pictures it looks like an aluminum plate, in the next picture the fuel passages are exposed.

(Note) This carb is from the late seventies, I don't know it you all will ever see the screw heads you see in this picture. If you do, the screws are called a "clutch" head screw. They hold well, just not always easy to find the screwdriver thatfits them.

Looking at the picture below, look closely at the bottom of the plate. I put two sharpie marks that represent the fuel entering this plate, then getting to the passage grooves.

This plate, just like so many of the parts of the Holley carb, are replaceable where the two holes at the bottom have different sizes to meet your needs.

Can the plate that is shown be replaced by a metering block? Yes, go to Jegs or Summit racing catalogs and you'll find kits to upgrade to a block design.

You'll learn this the first time you by the chrome fuel line that splits into two lines to feed the float bowls. I believe there is a 4150 and 4160 series carbs. The one with the block on the secondary side requires a longer fuel line than the carb using a metering block.

Next up I think we might look at the choke system.....