Stainless, Bushed PRW Rocker Arms
Stainless is a moniker for nickel based alloys and there are many types of “stainless” all alloyed differently with various types of other steels and elements. Think railroad track, that is a high nickel alloy, even higher in the 1800’s. Forging dies are high nickel alloys, I have cut a few of them. I’m not going to tell you that stainless is as strong as ductile iron, but with the ribbed design of those rockers it’s a good chance it is.
As a food-production equipment design engineer, I use stainless daily and I would like to point out that a high-nickel alloy steel is
not stainless steel, and that any steel in the 'stainless' family lacks the ability to be case hardened and most cannot be heat treated (which is not necessarily true for high-nickel steel). For mechanical usage, stainless is generally terrible, and I still contend that there is no reason to use it in any mechanical environment that is literally swimming in oil. I spend huge amounts of time designing around the compromises required by stainless steel.
The ribbed design is a structural consideration, not a material consideration, and yes, makes it stronger, but are they adding the rib because it was a good idea, or did they add the rib because of the piss-poor material selection? It's just like Craftsman wrenches; the new ones from China are appreciably thicker around the box-end, and this is due to inferior material.
That said, if the rockers work, they work (which, as purchased, they really don't after very much time), but stainless was a piss poor choice for this application. Typical Chinesium mindset: Shiny is better and many buzzword make product not inferior. Many particles of much strength to bring harmonious operation to your engine!
Now, I
have seen Chinese 'stainless' that literally had a sticker on it that said 'stainless', but it turned out to be cast iron that was simply painted silver. So there is a very real possibility OP's rockers might be some other material entirely than what was advertised!
