A new article with photos on the T/A & AAR rocker arms with a W2 / W5 rocker arm comparison

What is strange is that the part numbers on the rocker arm boxes do not come up when searched. The three bushed W2 rocker arm part numbers were P4120200-1-2. So no match there.
This is a mystery to me. The box has a 1993 date on the side. I checked the 1988 DC catalog and a 1997 MP catalog, but came up with nothing.


That's what has me stumped. I find nothing on the part numbers.