600 HOLLEYS

[DAVE460523]

I am rebuilding a pair of 600 Holley vacuum secondary carbs. I have read in various articles there is a hole in the right primary side of the main venturi. it is my understanding this hole controls the operational circuit of the secondaries. neither of my carbs has this hole can anyone tell me where the equivalent to this hole is on my carbs ? THANKS

[pamotorman]

every vacuum secondary holley I ever worked on had a hole in the primary venturi for a vacuum source to open the secondary. some even had hole in the secondary venturi for additional vacuum to help open the secondary.

[Ericnova]

Post up the List #'s off the carbs, so we know what your working with....there are literally a 100 different "600 Holleys".

[geraldtson]

Some of them are really hard to see. You have to look harder!!

[My427stang]

It has to be there, often it has a little shroud over it. Post the LIST number and/or a picture, if it really isn't there, maybe you have a set of mech secondary 450s?

[bill jones]

-this picture shows 1 long wire from passenger side front venturi out thru a hole (with that passage's end plug removed) near where the vacuum pot is mounted--and one other long wire from the right rear venturi area that intersects the first passage---and ends up going into the vacuum pot to pull vacuum on the diaphragm

wires out thru venturi vacuum ports.jpg

-this picture shows the short brass piece that is in some passenger side primary venturis ---that increases the venturi vacuum back into the vacumm secondary passaeways.

passenger side front barrel main vacuum port.jpg

-this picture is a close up of the passenger side secondary barrel's venturi vacuum supply under the blue scribble line---that helps increase the vacuum pull on the diaphragm.

passenger side rear barrel vacuum port.jpg

[bill jones]

-here's one more showing the outside of the main body where the wires exit.

-the shiny hole where the left side wire exits has had the lead plug removed and it's been threaded for a 10/32 setscrew to be the new plug.

-the hole where the wire comes out towards the center of the picture is the passage that connects to the vacuum chamber---normally uses a cork gasket or an O-ring to seal up that connection.

wires to venturi vacuum ports.jpg