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Old 10-09-2012, 07:17 PM
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Three hole carb spacers?

Hey everyone,

I was just thinking. Why don't you see any three hole carb spacers? Seems like it would be the best of both worlds. I have herd a few people have done it themselves but I have never seen any dyno charts or comparisons.
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Old 10-09-2012, 07:23 PM
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3 barrel holly

I had an old 3 barrel holly, they were good for 5ooo rpm and above. I think it was rated over 1000 cfm I just used it for parts.
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Old 10-09-2012, 11:34 PM
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Originally Posted by xxllmm4 View Post
Hey everyone, I was just thinking. Why don't you see any three hole carb spacers? Seems like it would be the best of both worlds. I have herd a few people have done it themselves but I have never seen any dyno charts or comparisons.
I'm at a loss to see any advantage. On a spread bore like you are showing, the motor runs all the time on the two primaries, which are the little bores at the front. When you mat the loud pedal, the larger secondaries kick in, both at the same time. I see no advantage in cutting out the wall between the secondaries. They're gonna flow the same, no matter whether there is a wall between the bores or whether there isn't. The only way you could make a difference is like timothale said, with a Holley 3-barrel because one long oval throttle plate has more area than two round ones like a Quadrajet.

Speaking of spacers, there is no arithmetical formula for making them work. Each motor is a combination unto itself and what works on one motor will not necessarily work on another motor.

Last edited by techinspector1; 10-09-2012 at 11:39 PM.
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Old 10-10-2012, 12:41 AM
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I have never done any dyno testing of 3 hole spacers.We did do a few pulls with different 4 hole spacers and open spacers.remember when nascar use a spacer/restricter? The 4 hole spacer that has has porting done sometimes adds power.what I will try to describe is:
looking through the top of the spacer you see 4 holes with a flat bridge between the holes.Under side looking up you see the center cross has been ported to a point like a bullet shape. we tested same thing with all 4 holes chamfered and spacers with no dividers. The particular engine we were testing liked having the bullet nose cross the best.
some intakes are available with an inverted bullet on the intake floor.It does not work in every situation.

Like tech said,every engine has a different need
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