The LHS lever goes to a brake on the front end of the gearbox.  In this version it is like a clutch assembly.  Sort of a hand brake I think. From one on whose grader this barely works and the rear wheel brakes are non-existent.  As the previous owner said - use the blade, and sometimes it doesn't go down fast enough.

 

The plugs on the head are the "energy cells" of the Lanova injection system.  Which, in my view, was a work-around of Ricardo's patent of the usual injector/precombustion chamber/ piston area sequence.

 

The Lanova system seems to have happened with a number of US diesels.  Basically it involves a horizontal injector blowing fuel across the top of a flat-topped piston into the energy cell where magic things happen according to the book.  The manual has dire warnings on lapping the various bits in if removed and not cleaning with metallic objects.

And you need to follow the injector spray patterns that are acceplable. 

 

And, IMO and sarc/on, if all these magic things had happened, Allis's next move wouldn't have been to the vertical injector with combustion chamber in piston setup of the 10000 engines.  For which I'm told there is a hell of a lot less head trouble.

 

While the fallback was a GM 4/71 as in AD4, with 20/20 hindsight I'd probably have gone for a 10000 if I hadn't tripped over the short motor we got.  And an interesting re-power would have been a Fiat OM3 as in a FA 10 dozer (we've got one of these), which is similar power, came in industrial PTO form and was used in some headers (combines to you).  Similar power and less fuel use.  I'll need reincarnation to try this though.

 

Others will probably dispute both the above!