Sonic test

Chuck. As John and Frank brought up, stick with the thicker wall scenario versus going "as big as possible" in the blown application. Cylinder wall flex ends up being a player when adding a supercharger to the mix. Although adding some block fill can alleviate some of the flex, just keeping the cylinders walls thicker is the best insurance. When initially sonic checking Randy's C2 block it was good for being bored 0.110" over if being normally aspirated but because of the blown nature, I just cut that value in half and kept the finished bore size to 3.800". Here's the sonic check results of Randy's block after final boring.

These are all the minimum values when sweeping the sonic check probe the length of the cylinder wall.

After sonic checking a variety of Y block castings, there is no set rule for one block casting number being better than another. I've now seen 272's that would bore out to 312 plus while others are iffy at 0.060" over. The C2 blocks seem to be the most predictable but core shift is still an issue thus forcing offset boring if going for the larger bore sizes. Sonic checking is a prerequisite if wanting to be sure of what you have.

Lorena, Texas (South of Waco)

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MoonShadow	Posted 18 Years Ago
Supercharged Group: Forum Members Last Active: Yesterday Posts: 4.6K, Visits: 38.2K	This is the result of the sonic test on my spare 292. Shop says there is too much core shift to make boring reasonable. Opinions? Chuck Y's guys rule! Looking for McCullouch VS57 brackets and parts. Also looking for 28 Chrysler series 72 parts. And early Hemi parts. MoonShadow, 292 w/McCulloch, 28 Chrysler Roadster, 354 Hemi) Manchester, New Hampshire
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Ted	Posted 18 Years Ago
Co-Administrator Group: Administrators Last Active: 1 hour ago Posts: 7.4K, Visits: 205.8K	Chuck. As John and Frank brought up, stick with the thicker wall scenario versus going "as big as possible" in the blown application. Cylinder wall flex ends up being a player when adding a supercharger to the mix. Although adding some block fill can alleviate some of the flex, just keeping the cylinders walls thicker is the best insurance. When initially sonic checking Randy's C2 block it was good for being bored 0.110" over if being normally aspirated but because of the blown nature, I just cut that value in half and kept the finished bore size to 3.800". Here's the sonic check results of Randy's block after final boring. These are all the minimum values when sweeping the sonic check probe the length of the cylinder wall. After sonic checking a variety of Y block castings, there is no set rule for one block casting number being better than another. I've now seen 272's that would bore out to 312 plus while others are iffy at 0.060" over. The C2 blocks seem to be the most predictable but core shift is still an issue thus forcing offset boring if going for the larger bore sizes. Sonic checking is a prerequisite if wanting to be sure of what you have. Lorena, Texas (South of Waco)
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Sonic test

Sonic test

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