The rods in stock motors have the piston pins pressed into them, and the piston floats around the fixed pin.
A full floating pin rides in a brass bushing in the rod that is the same bore as in the piston, and is kept from escaping by snap rings or spiral lock rings in the sides of the piston.
Bushed rods are preferable because the piston and rod can be assembled much more easily without the use of special tools and without the chance of screwing something up, and because a full floating pin will have less wear and friction (an etremely small advantage though), and if excessive load is forced upon the piston, the replaceable rod bushing tends to take the damage rather than the pin bores in the piston.
The use of pressed pins was likely for greater efficiency in mass production of many car engines. They are not used in industrial motors to my knowledge.
