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Old 10-29-2010, 10:14 AM   #26
prostreetC-10
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Join Date: Oct 2008
Location: Orygun
Posts: 5,527
Re: Holley 3310 750cfm Rebuild

I just want to say this for all the other people that might read this as I have already talked to C20-67_N_MO.

I sell a lot of HP carbs because I am filling a "want" in the market of people that think these carbs look "BAD A$$". There is a slight amount of gains at the track if you are going from idle/rev limiter to WOT. They flat out are not nearly as good on the street. One of the best things you can do to any carb on an upgraded motor is to actually mill the choke flat. ON A STREET MOTOR, there is actual flow bench proven data that leaving the little part of the choke that separates the primaries and secondaries when milling the choke will provide benefits on the street. That's why it's funny when people will mill the choke and then spend hours with a Dremmel taking out that part and hurting performance....all in the name of looks!!!

Please don't buy into the 25-40 hp gains from a simple main body swap although I'm sure that happened one time on a motor in Tim-buck-two (or was it on that dyno next to the snowball in hell). I guess you could get it from doing taking a 650 and doing the 750 swap on a motor that was starving for more fuel.

I really think the best reason for that main body swap is if you have a 650 or a 700, since they both use the same base plate and bowls. It's not because of the contoured venturies but rather the fact that you will be upgrading from the straight leg boosters to the downleg. They say the main body will work with 650-800 DP. Problem is that the 650 and 700's have too small of a PVCR (power valve restrictor channel) and should be opened up. The 650 is literally a pin hole. 'Course I feel that just about any DP can benefit from having the PVCR enlarged. It can be a great mod to help with off idle/low speed/cruise stumbling. It will also allow you to jet down just a little to get a leaner cruise A/F ratio thus helping gas mileage "a little".

I opened up the holes in my 450's to the size bigger than an 850. Made a big difference at very low speeds on that huge plenum.

Last edited by prostreetC-10; 10-29-2010 at 10:20 AM.
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