What is the size of bolt for small block Chevy for motor mount to frame?

The standard bolt size for the motor mount to frame on a small block Chevy is typically 3/8"-16, with a length of around 1 to 1.5 inches, depending on the specific application and mounting brackets used. It's important to verify the specifications for your particular model and year, as variations may exist. Always ensure to use the proper grade of bolt for safety and durability.