Thread: power valve?

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Hey, everybody. Got just a quick ? about holley power valves. I know you check your vacuum at idle and divide that in half to get the size for the valve- but the catch I have run across is do you check it in park or in drive? Tranny is 350th automatic. My vacuum in park is 14 in. and in drive it it 9 in. So do I get a valve of 4.5 or get a valve of 7 in? Thanks.

thank you, it's been a little rich but have been running the 6.5 that came in the carb to start with. Gonna go get one and see what happens.

Warmed it up and checked in gear with idle about 6-650 rpm and got the reading of 9in. Off to get grungy