Dart sends the block with a 4.250 bore that has a nice crosshatch finish. Each bore is still checked with a dial bore gauge. This measurement will let us know the piston-to-cylinder clearance and also check the consistency of the bore sizes. We have 0.0050 piston-to-wall clearance, which is right in the middle of JE's 0.0045-0.0055 recommended range for a nitrous application. Hey, juice happens.