I’ve spoke to many people including TAD, Perkins in the U.K. I’ve even paid $150 because I was promised a shop manual for my 1983 4.236. And what I received is a 1993 shop manual ( which I already have) even though I gave them my
engine serial. The 1993 is not accurate for my
engine. Maybe my manual does not exist anymore or never did with so many iterations /countries of origin, etc. but I will still strive in full skepticism mode