ok i have a Holley 600 and i have a question for anyone who knows it.
There is a vac line in the base plate and 1 in the metering block i don't get any suction from either of these until the car hits 1500 RPM, Is this normal?

 

Yes it is normal for the one in the metering block. That one is for vacuum advance, which generally should not be active at idle. It's called "ported" vacuum, because it's obtained from a port in the throttle bore that's just above the throttle blades when they're closed, and opening the throttle exposes it to vacuum.

The one in the base should be full-time vacuum.

 

Yeah thats what i thought but i have a vacuum guage and i hooked it up to eatch of them and both had the exact same readings and they only started working at 1500RPM and up, this leads me to the next question there are 2 vac lines comming off the Holley one goes to the vac advance on the dis and the other goes to a little block with wires comming off of it. what is this block and should it have constant vac, if so should i run the vac line direct off the manifold to it?

EDIT:


Anyone know what these are and why theye need vac lines?

 

Any one know what the little box is it has a plug with wires coming off of it but has a vac line from the carb going to it?
it is on the LHS of a group of wires and plugs (i have no idea what any of them are for, there is another vac thingy but that is facing up and is blocked off).

 

Carburators have 2 types of vacuum available for use.
Ported Vacuum - available only when throttle plates open. Zero vacuum at idle.

Manifold Vacuum - very strong at idle, dips quickly when throttle plate is opened.
Use a vacuum gage and watch if the vacuum goes up or down when you crack the throttle with engine running. Should have 15 - 20 inches at idle manifold vacuum. zero ported vacuum.

 

Yeah have tested both lines on the Holey and they both wont work during idle (revs have to be up).
The big one from the base of the Holley that goes to the brake booster is on all the time (as normal).