[llwta76]

For some reason the nipple above the mixture screw in the metering block I have is supplying full manifold vacuum.

[PAUL K]

That usually happens when the idle speed set screw is turned up to high. Take the carb off and look to see if the vacuum port is exposed.

Tom V has and excellent thread in the street section that explains the proper location of the butterflies that will prevent your issue.

[JSchmitz]

Originally Posted by PAUL K

That usually happens when the idle speed set screw is turned up to high. Take the carb off and look to see if the vacuum port is exposed.

Tom V has and excellent thread in the street section that explains the proper location of the butterflies that will prevent your issue.

And, if you have the throttle blades open that far, it's probably dripping fuel from the primary boosters too.

[Tom Vaught]

YEP or the Fuel Level in the Bowls is set wrong too.
If the fuel bowls are stock bowls, then the fuel level needs to be just below the bottom of the hole when you take the brass screw out of the side of the bowl.

Tom V.

[llwta76]

From some research I did some 3310 (780) did not have ported vacuum source. I bought this carb a few yrs ago . Is from a 60s chevelle 396 . I followed the channel from the vacuum connection to the base of the carb to verify. Is full vacuum.

[JSchmitz]

Originally Posted by llwta76

From some research I did some 3310 (780) did not have ported vacuum source. I bought this carb a few yrs ago . Is from a 60s chevelle 396 . I followed the channel from the vacuum connection to the base of the carb to verify. Is full vacuum.

Interesting. I went through a Factory 396 Holley for an old neighbor years ago. I tested it on my '65 Chevelle. That thing worked fantastic! He decided to go TPI and sold the carb to someone real cheap. I was kinda pissed that he never used it and I didn't get a chance to buy it! Lol!

[Tom Vaught]

Originally Posted by JSchmitz

Interesting. I went through a Factory 396 Holley for an old neighbor years ago. I tested it on my '65 Chevelle. That thing worked fantastic! He decided to go TPI and sold the carb to someone real cheap. I was kinda pissed that he never used it and I didn't get a chance to buy it! Lol!

I have about 20 of the factory Holley #3310 Holley carbs (Chevy #s on the airhorn and application like EH for a BB Chevy). How many do you want to buy?

Tom V.

[kyle_blake]

I have a 3310-3 main body for sale but it is not from a factory muscle car stock item. mine with the metering block verified as ported source with vac gauge hooked up at idle.