It is a type of engine for a car.
The stock bore was 4.125". The bore of a 406 would be 4.155"
The bore and stroke of a 406 small block Chevy (SBC) engine typically measure 4.125 inches for the bore and 3.80 inches for the stroke. This combination allows the engine to displace 406 cubic inches, making it a popular choice for high-performance applications. The larger bore and stroke contribute to enhanced power and torque characteristics.
.030"
a 400 small block Chevy has a 4.125" bore.
get a big block or bore it 54 over
4.125"
4.030
A small block Chevy has a 4inch bore. When you bore one 30 what you are doing is removing .30 thousandths from the cylinder. That would make the bore 4.030 or turn a 350cid into a 355cid.
3.740 inches
The bore and stroke.
4inch bore 3.25 stroke formula bore x bore times stroke times .7854= cid
4.165"