It,s been asked many times. Somewhere in the websight explains it but I,ll give a quick def.
The old Chevy 6,s used slotted screws on their oil pans & valve covers. Slotted screws in the hardware business are commonly called stovebolts. The farmers called the old Chevys "Stovebolt 6,s." Through the years it has been used to describe any old chevy. The early V-8,s did use "sovebolts" on there valve covers.