To manufacture V6-type and V8-type engines by commonizing amounts of a cylinder-offsets in a connecting rod structure of a V-type engine, and commonizing design manufacturing and maintaining facilities, and to provide an optimum strength and rigidity of a crankshaft and reduce a number of exclusive components in the V6-type and V8-type engines.

When using the V6-type engine, each large-end center of two connecting rods connected to each crankpin between adjacent crank journals of the crankshaft is offset each other outwardly from the center of each cylinder. When using the V8-type engine, each large-end center of two connecting rods connected to each crankpin between adjacent crank journals of the crankshaft is offset each other inwardly from the center of each cylinder.