LW cam followers

[mdt-son]

Hi all,
According to the Technical analysis by John Allen,

https://www.jampot.com//TechTips/Single ... alysis.pdf

cam followers received an update for 1962 (or was it 1963?). Until then, cam followers carried p/n 042071.
I would expect revised cam followers to carry new part numbers, but can't find them.

Another thing has puzzled me: Going by images, camshaft followers appear to have different lengths. The 1960 spares list doesn't account for more than one follower, 042071, yet there are two. It could be a printing error, as the 1959 LW spares list numbers them as 2. I've seen a picture of one follower which is stamped 042072. That could be a casting number only.
Is there an update to the 1960 spares list confirming the two followers have p/n 042071 & 042072, or 2 off 042071 ?

Is there a LW expert here who may help out?

- Knut