Vacuum Secondaries

I had a tri-power setup on my 409 chebby with vacuum linkage to the front and rear carburetors. I was young and couldn't leave it alone so I took the vacuum linkage off and installed mechanical linkage to get the full effect of the three carburetors. OMG what a difference it made, now I had more motor than I had brakes-but that's another story.
I have to chime in that my street only Barracuda automatic loves the VS Holley I installed on an LD4B. I did install an Innovate wide band to help me tune it. I bought the quick change secondary spring change kit and studied the instructions to memory. Under all conditions I can watch the secondary's open and close on my wide band but because it has the correct springs in it you cannot feel any change in the fuel supply, it just keeps pulling and the wide band richens up. I know VS is not for everyone but it was the right choice for me and my build combination.