Chevy Nova Forum banner

1 - 3 of 3 Posts

406 Posts
Discussion Starter #1
Rebuilding a Holley #3310, should the check ball be left out? I am using a quick change kit and starting with a yellow spring.

When I worked for Holley, I addressed this issue three different ways:

I took a small chisel and made a groove under the ball, in the seat area of the housing, so the vacuum would actually reach the diaphragm

i removed the ball and added a drilled slug in its place, starting with a .055 oriface, adjusting from there. The 5.0 Mustang OEM Holleys use this setup.

Last, I made a slug with a .150 hole, then added a mixture adjustment screw from the top, into the drilled oriface, with a nut and small O ring on the screw in the cover to seal it up. This allowed me to change the overall vacuum signal by adjusting the mixture screw into or out of the oriface.

I also made a tube with a 45 degree angle that closed off the secondary hole in the secs pull passafge in the body, and made it fit into the primary bore. I used copper tube, then inserted it from the rear bore hole on the side of the carb, just behind where the dpaphragm bolts to the carb. This way, I had a better signal, from a masked pull tube in the primary bore, and no secs bleed.

If you look at the design, the ball is sucked into its seat by the vacuum attempting to open the diaphragm, and seals the vacuum off from the diaphragm if the ball seats correctly. Making a controlled small pull oriface helps.
1 - 3 of 3 Posts