1. Cylinder Wall Thickness: If the cylinder walls appear thinner than usual, it's possible that the engine has been over bored. You can measure the cylinder wall thickness using a bore gauge. The standard cylinder wall thickness for a 350 Chevy motor is approximately 0.185 inches. If the bore gauge reading is lower than this value, it's likely that the engine has been over bored.
2. Honing Marks: Over boring involves resurfacing the cylinder walls to remove any imperfections or irregularities. This process typically leaves behind visible honing marks or cross-hatching patterns on the cylinder walls. If you can see these honing marks, it indicates that the engine has been over bored.
3. Piston Clearance: Over boring increases the size of the cylinder bores, which requires either larger pistons or reduced piston-to-cylinder wall clearance. If the engine has been over bored without properly addressing the piston clearance, you may observe excessive piston slap or other issues related to excessive clearance.
4. Engine Serial Number: Some 350 Chevy motors feature a "VIN code" located near the cylinder block. If the engine has been over bored, there may be an "X" suffix added to the serial number, denoting that the engine has been oversized.
5. Valve Clearance: Over boring can also affect the valve-to-piston clearance. If the engine has been significantly over bored, it's possible that the valves may come into contact with the pistons, causing damage to the engine.
It's worth noting that determining if a 350 Chevy motor has been over bored can be a complex task that requires some technical expertise and specialized tools. Consulting with a qualified mechanic or engine builder is often the best approach to obtaining an accurate assessment of the engine's condition and whether it has been over bored.
