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Old 04-11-2006, 12:10 PM
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Holley 850 CFM Vacuum Secondaries.. PITA..!!

I'm running a GMPP ZZ502 Deluxe which comes with a Holley 850 CFM Vacuum Secondary Carb Model # 0-80531. This carb is flowed for the 502 motor and the Holley part Number is only for this carb for the 502. The motor is in my 65 Corvette Cp with a Keisler 5sp OD Tranny and 3:36 rear.

I installed a filp top lid on the Vacuum Secondary chamber which lets you change the spring that controls pull in time for the secondaries. I started with the lightest spring. But I was not able to get it to bog like they say should happen with the lightest spring and then work up.

There was an improvement in the responce time and feel ..but not like you would think. It still just doesn't have that "Rip out feeling". It does start to pull faster then before but there is still that waiting for the secondaries to open feeling.

Now I have read all the do's and don'ts that come with the spring kit... you know like ...don't remove the ball check valve ..or don't cut the spring....Blah Blah Blah. And I also read al the poop about the air cleaner.

Now a friend of mine who nows his way aroud holleys says to remove the Ball Check Valve in the Vacuum Chamber.. and move up one spring to see what happens.. Of course the techs at Holley on the phone tell you this is a No No.

Have any of you run into this situation?? And or what have you done to improve the secondary responce..Now I'm not looking for a Bog ..or a Lag feeling...just a get T F up and go feeling ..

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