Abstract: A piston/connecting rod assembly is provided for an internal combustion engine. The piston has a piston pin bore which receives a piston pin. An end of a connecting rod has a connecting rod bore which receives the piston pin, and the wall of the connecting rod bore directly engages the piston pin, without a bushing therebetween. The connecting rod bore is symmetrical, and has a diameter which varies from a smaller uniform diameter central portion to a larger diameter portions at either end thereof. The connecting rod bore also has a profile which is symmetrical about a central plane which is perpendicular to a central axis of the connecting rod bore, and which is elliptical or quasi-elliptical on either side of a central uniform diameter portion.