I was moving stuff around the garage and happened to that the rods from my ’33(366) and ’35 (385) engines side by side and made a couple observations
The ’33 rod is about 3/8 of an inch LONGER than the ’35, the clean one.
The next thing I noticed is the 366 has a single cylinder wall oiler hole
The 385 rod has 2 cylinder wall oil holes.
So, it appears that if the rod has a single oiler hole it is for a 366 and if 2 then it is a 385.
That’s my theory anyway.