Shear Plate
by Scott Martin ©2002

SHEAR PLATE

A What?! is usually the retort I get when mentioning this.

What it is, is a carb spacer worth roughly 20 horsepower.

Got your attention? I thought it might, and how simple it is will, well, astound you.

Ok here's the skinny. Its basically a four hole carb spacer that helps provide and distribute the "mix" into the plenum a little better. By, one, isolating the venturies from harmful reversion and, two, by isolating the carbs metering circuits and bowls from vibration. Thus allowing it to do its job without the fuel in such a constant "excited" state due to engine vibrations and, having reversion confuse the "signal" to the boosters.

Think about it for a minute,

Now, to try to tell you how to make one. Bear with me please. Ok take a plane jane four hole spacer at least 1 inch thick. Now taper the holes about 7 degrees from the carb base down to the plenum. Then machine a groove around each hole with and 1/8th inch ball mill 1/16 to 1/8 deep, The groove helps keep reversion( the black crap your seeing in the plenum ) from going up the throttle bores. And finally machine a groove around the perimeter of it to accept a rubber "0" ring ( you can machine a groove on intake to accept also if worried about losing "O" ring to engine vacuum).

Now install and tighten down using a 10 thousands feeler guage to assure a level fit and enjoy.

Feel free to ask questions if your having trouble "seeing" it in the minds eye or just the hows of, Hows it work?

Scott Martin email

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Other Resources: Secrets of a 740hp Winston Cup engine, Home Porting the Holley Carb, Hidden Head Porting

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