Block Talk (Part 1): What to Look For When Buying a Used Engine Block
Anyone who has ever spun a 9/16-inch wrench on a hot rod knows the engine block is where it all begins. There are lots of options available—new and used, iron and aluminum, OEM and aftermarket.
We’re going to examine a typical V8 engine block—in this case a Chevrolet Performance Bowtie iron block for big Chevy engines (part number NAL-19212195 from Summit Racing) to show you what goes into a modern engine block, and what to look for when buying a used block or getting a block prepped at the local machine shop. The information presented applies to other OE and aftermarket blocks as well.
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I’m confused. The BBC bore spacing is 4.84″. If you bore the cylinders out to 4.60″, the thickest the walls can be is the centerpoint of the 2 cylinders, which is 4.72″, which would make the cylinder wall thickness 0.12″, not 0.25″. Where am I going wrong?
Jon K Do your math again.One half of 4.6 is 2.3 same for the next cylinder 2.3 + 2.3 = 4.60 4.84-4.60 = .24 wall thickness between the two cylinders