I have here a gem of mechanical engineering from the past. I'd say the deep past, but its date of origin is approximately the same as my own. I'll leave that be.
What this is, is a rocker-arm from a Wright R3350, the engine too much hastened into production for the B29, and which later matured into a very substantial civil powerplant.
The rocker is a heavy thing. At first I had reservations about that. Rockers for the P & W R4360 were much slenderer and lighter. But there's a reason; the pushrod approaches the Wright rocker at about a 30 degree angle, and the hefty diameter of the pivot, provided with a three-row rolling-element bearing, exists to accept the combined radial-axial loading from the skewed pushrod.
The other end of the part has a threaded ball-socket as a clearance adjuster, and it is provided with a lip that prevents its ever unscrewing all the way and cau. Then the usual maze of oil-return pipes, with which large radial engines were always festooned, carries away the spent lube to scavenge pumps.
The giant pivot bearing is also lipped on its OD - to accept the axial thrust from the pushrod. It has a single row ball bearing in the center, flanket by a maximum-complement roller set on either side -- all retained by snap-rings. These snap-rings have no function other than to hold the rollers in place; thrust is taken on the flanks of the ball bearing's races.
The valve end of the rocker bears a large roller, and there is a radiused cutaway below it to allow the rocker as a whole to be crowded as close as possible to the valve-spring stack.
The rocker beam appears to have been aluminized -- perhaps for corrosion resistance up in the nasty atmosphere of the rocker-boxes.