I bought a sonic tester, and want to know whats the min. thickness specs of the cylinder walls, before or after boring the block. On the thrust side and pin side. Like i said the minimum wall thickness. This is a aluminum LS3 block that im working on. And what kind of material is the sleeve made of, like iron or steel or what. Trying to set the frequency for the tester. mild steel or(iron) shows on the chart 5900m/s and cast iron 4600m/s .Does and body know the true frequency. And yes ive done hours of searching, and nothing.