Whats the proper why to determine what size power valve your carb needs? I have a 750 mech. sec. speed demon and I've heard a couple of different whays to do it. Was just wondering what the proper why is.
Thanks.


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406SBC
-DART SPORTSMAN 2 HEADS
-RPM INTAKE
-750 SPEED DEMON MECH SEC. CARB
-HEDMAN HEADERS
-COMP CAM EX .507/.510

 

Opinions vary...the method I like is stick a vacuum gauge on you car for a day and drive around normally. Note the readings at idle, part throttle, and cruise, and get a PV rated 2" below the lowest reading.

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"American made baby. 100% American iron. The muscle among the masses. My hero. Yep, you can take your ergonomically designed, space age, computer controlled, 4 door, cup holding map lighted split double wishbone split fold down retractable cargo covered moon roof piece of transportation and keep it. For I have felt the thunder. And I know the difference!"
JSP Motorsports
ICON Motorsports

 

I agree with Jester the best way would be a vacuum guage connected and see what you are running at idle then go 2 numbers lower that your vacuum reading.

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383 86 Camaro Z28
10.5:1compression Dart Pro 1 Aluminum heads 215cc>2.05/1.60 valves,400 steel crank,cam specs:224/234 at 050 525/525 lift,3500 stall converter,shift kit,3.42 gears,770 Holley Avenger,Victor Jr. Intake,true dual exh,Hooker headers with 40 series Flowmasters,MSD Coil and Module.

 

I always heard u where suposed to half the # than add .5 . So I just get one 2 #'s lower than?


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406SBC
-DART SPORTSMAN 2 HEADS
-RPM INTAKE
-750 SPEED DEMON MECH SEC. CARB
-HEDMAN HEADERS
-COMP CAM EX .507/.510
-1.6 roller rockers