hi I got a Holley 650 DF DP MS and I want to bolt it to my 305 (it`s not stock lol) but I have a problem the 1 time I bolted it to the engine it had a high pitched sqealing vacuum leak to it and reved at 2500 RPM at idle so I took it off.... now today I wanted to try again and I bolted it to the engine with 2 gaskets this time and the high pitched noise went away but now it idles at 4500 RPM YES 4500 , is this a sign that the power valve is blown??, I don`t know much about Holley`s and lost my Holley book so I`m not sure whats wrong with my Holley? I have a 600 SP SF VS Holley on it that I want to replace with the 650, and yes I`m goin to a 350 VERY soon like in the next month and REALLY want to run the 650 on it

 

Sounds like you've got one massive vacuum leak or one really screwed up carb. Power valve blowout will make it run pig-rich but won't cause a high idle.

 

I looked closer at the 650 today and found out that butterflies arn`t closeing all the way at idle So I got the take the primary shaft out and lube it all up and straghten out a couple of bent parts I found and try again

 

Using more than one gasket can allow baseplate to flex, even crack. One should be enough, maybe plate was already warped so it wouldn't seal.