An internal combustion engine includes a crankshaft having a first web portion defining an inner opening and defining an undercut proximate the inner opening, a second web portion defining an inner opening and defining an undercut proximate the inner opening and an inner bearing portion that engages with the inner opening of the first web portion and with the inner opening of the second web portion. First and second pushrods each have a piston end and a crankshaft end. The crankshaft ends of the first and second pushrods each have a concave surface placed over different portions of the inner bearing portion between the first and second web portions, and each further have shoulders adjacent their respective concave surface that engage with the undercuts of the first and second web portions.