Read the first sentence. What is the first factor mentioned? Material.

Then they go into great detail about the piston skirt design, that is true. There must have been some controversy in the piston market at that time, to cause them to put so much emphasis on it. But compared to material IMHO it is a minor consideration. I have never seen piston skirt oil drainback holes mentioned in any other catalog or website. I hadn't seen this catalog either, so it's interesting to see it now. This factor isn't mentioned in their current catalogs, as far as I know.

Of course you are free to disagree.

R.