Holley Swap, hookup questions

[alpentolic]

When I bought this '74 Box Van I was handed an Edelbrock Performer and an old Mopar-Specific Holley 4160 carb (List 6495). The PO had split the exhaust into duals and said there was a mild summit cam in it, but the old 2bbl is super worn out so i am putting this setup on.

It has a couple fittings I don't recognize from other 4bbls. The elbow coming out of the float bowl I'm guessing is an overflow? But the other side doesn't have one. It pulls right out.

The tube coming out over the top of the choke there is pressed in and goes straight through to the top of the intake. A vent tube I don't recognize I guess.

While I'm at it, I'm trying to find a good place to connect my pcv hose. I couldn't find much on what openings in the Performer intake are vacuum. I was told it was the rear 2. One I have hooked up to Power Brake hose (seems weird to run it all the way to the back of the intake but that's how the stock one was set up). The other I put a 3/8 fitting on, but not hooking up until I know.

I'm sure I'm leaving things out so thanks for helping and let me know. Much appreciated!

 

[RJRENTON]

When I bought this '74 Box Van I was handed an Edelbrock Performer and an old Mopar-Specific Holley 4160 carb (List 6495). The PO had split the exhaust into duals and said there was a mild summit cam in it, but the old 2bbl is super worn out so i am putting this setup on.

View attachment 952803

It has a couple fittings I don't recognize from other 4bbls. The elbow coming out of the float bowl I'm guessing is an overflow? But the other side doesn't have one. It pulls right out.

View attachment 952804

View attachment 952805

The tube coming out over the top of the choke there is pressed in and goes straight through to the top of the intake. A vent tube I don't recognize I guess.

While I'm at it, I'm trying to find a good place to connect my pcv hose. I couldn't find much on what openings in the Performer intake are vacuum. I was told it was the rear 2. One I have hooked up to Power Brake hose (seems weird to run it all the way to the back of the intake but that's how the stock one was set up). The other I put a 3/8 fitting on, but not hooking up until I know.

I'm sure I'm leaving things out so thanks for helping and let me know. Much appreciated!

My guess on the elbow connection....since its coming out of the primary metering block, it appears to be the connection for the vacuum advance to the distributor. The other connection may be the PCV connection. The PCV connection must see intake manifold vacuum. The other straight tube shown in the last pix may be the clean air connection to the choke, although it appesrs that the choke coil is electrically heated.
BOB RENTON

 

[alpentolic]

Much appreciated. Plugged most of those off and it is running pretty good. Are you familiar with a brass balance tube on some of these old Holleys? It sits below the larger feeder tube and is a much smaller diameter. In the diagram it shows an o-ring and small round gasket to seal it, but I didn't get anything in the rebuild kit i bought and don't see how in the world even a tiny o-ring can make a seal on any surface this tube touches.

It is leaking slightly there and I'm stumped. I have another post with pics I just started. Thanks again!

 

[RJRENTON]

Much appreciated. Plugged most of those off and it is running pretty good. Are you familiar with a brass balance tube on some of these old Holleys? It sits below the larger feeder tube and is a much smaller diameter. In the diagram it shows an o-ring and small round gasket to seal it, but I didn't get anything in the rebuild kit i bought and don't see how in the world even a tiny o-ring can make a seal on any surface this tube touches.

It is leaking slightly there and I'm stumped. I have another post with pics I just started. Thanks again!

Which rebuild kit did you use? Can you post the Holley numbers, usually stamped into the air intake (air horn) on the back side? There will be List # R________ and a numeric date code like 1234 where the first 3 digits are the day of the year snd the 4th digit is the year built. There are many variations of the basic Holley design. Sometmes genetic rebuild kits do not cover specific models.
The fuel balance tube is sealed with a small o-ring and back up washer at both ends, which compresses the o-ring ... just watch the order of assembly...if the washer is not used or reversed, it usually leaks. This balance tube is not under fuel pressure like the supply is....just tge static fuel level in the bowl. The supply tube is aluminum with an upset ridge and a large o-ring at both ends. The o-ring is easy to pinch when assembling. I usually coat this o-ring with a light film of silicon grease to prevent it from getting pinched.
BOB RENTON

 

[alpentolic]

It was the Holley brand kit for a 4160. Below is the list pic and another showing the setup. I was playing with the smallest o-rings in the rebuild kit and didn't see how in the world it fits to seal the hole and not get interference from the metering body, gasket or casting. There wasn't a flush surface to be found, but then again I'm a novice.

I really appreciate it.

 

[RJRENTON]

IMO...
In the last pix, in the highlighted circle is the "sub-metering" or back-up plate that supports the metering plate. On the back-up plate (which sits on the blue sub plate gasket) is the pressure "fingers" which applies force to the small flat washer that presses on the balance tube O-ring, flattening it slightly causing the O-ring to seal against the balance tube. Typically, the balance tube and its O-ring and flat washer are installed b4 the metering plate, back-up plate and the blue sealing gasket is installed and before tightening rhe meteting plate's attaching screws, at which time the entire "sandwich" is tightened. The balance tube's O-ring fits into a shallow recess, which contains it, and the small flat washer would press on the O-ring, expanding it slightly to seal the tube. Hope this helps....you will need to remove the secondary metering components to see the O-ring recess and its back up washer. The rebuild kit instructions should have pointed this out. You may need to replace the blue gasket as it appears to be scored deeply and may not seal again.
BOB RENTON

 

[alpentolic]

You were correct I needed the o-ring and washers to seal up that balance tube. Hopefully all buttoned up against leaks now.

Still having some other fitment issues but at least the gas is staying where it should! Thank you