What do they bore on a 350 motor to make it a 355?
The cylinders .030 over size On a 350 the cylinders are bored from 4.000 inches to 4.030 inches. This is not done for performance. 5 cubic inches will not give any significant gains in power. This is done during a typical rebuild to either cleanup the cylinder bore or to remove any taper in the cylinder walls from normal wear. Replacement pistons usually come in .030 increase increments. .030, .060, etc.
