Vacuum Advance at Idle

Hi All,

I am trying to tune the timing and carb on my 440.

With the vacuum advance disconnected and plugged, I can get things to where I am happy with them (vacuum, timing, idle speed), but as soon as I plug in the vacuum advance, the idle speed shoots up like 500 rpm, and I can't get it back below a 1,000 or 1,100 rpm even with the idle speed screw backed all the way out.

I know I want to run the vacuum advance, but I feel like something isn't right, maybe with the vacuum advance canister?

I am going to do a little more research, but any advice in the meantime is appreciated.

Thanks.

Greg

You are using the wrong vacuum port. You want what is called ported vacuum. It doesn't have vacuum at idle. The vacuum nipple is above the throttle blades when they are closed.

Hook it up to the ported port, if you see two in the base plate, it'll be the higher of the two. A Holley port will be on the right (passenger) side of the primary metering block.

Okay, thank you, that is exactly what I was just starting to figure out on my own.