From the perspective of 60+ years' experience building engines, the material a ring is made of has a lot less impact on a successful job than the condition of the cylinder it's being installed into, and the preparation the cylinder gets prior to engine assembly. Most of the exotic material rings were developed to compensate for them being installed in tapered bores, or improperly honed cylinders. At 2K RPM, a ring running in a taper-worn cylinder is flexing 60 times per second to try to maintain a seal with the cylinder wall. To do that, rings were developed with lots of spring tension, and it was necessary to incorporate a self-lubricating material (Moly) or a hard chrome facing to minimize friction wear. A straight (rebored) cylinder with no taper stops ring flexing, and also eliminates the need for exotic ring materials. Proper cross hatch honing creates the right conditions for quick ring seating, and the crosshatch also traps a microscopic layer of oil to keep the rings and piston skirts lubricated during ring break-in.
Some engine blocks such as the Hudson inline sixes and some of the early Ford OHV V8's had such a high nickel content that a chrome ring simply refused to seat. Those blocks also wore at such a slow rate that a re-ring job didn't need to have the block bored and new pistons fitted. GM has always used a much softer (less expensive) alloy in their block castings, so a rebuild with chrome rings resulted in pretty good ring seating, but at the expense of rapid cylinder taper wear.
Jerry
