Hi Dave

I thought Allis was out of Detroits around 1954?  Or did they start using Budas?

Next question -  did the "Forty Five" come out 55 - 56 era then?

If that book has serial numbers try 524 - 204 for a serial number.

The "gotcha" is that is an Australian production number  which makes reading a US parts book an interesting chore.  By the "It has this but it doesn't have that" system I've got ours to within a couple of hundred.

The Australian ones had Hydreco hydraulic pumps - must have been a licensee building them here I guess.

This also turned up in the search - 6 reverse, 2 forward gears

https://www.mytractorforum.com/31-allis-chalmers/253456-allis-chamlers-ad-40-road-grader-transmission-gears.html" rel="nofollow - https://www.mytractorforum.com/31-allis-chalmers/253456-allis-chamlers-ad-40-road-grader-transmission-gears.html

The engine with supercharger was Lanova injection and might have just continued from what Buda was making when Allis bought them.

If you're being a purist - with that engine  it is a "Forty Five" (i.e. spelled) and the later ones with 10000 series engines are "45's (numeric).  But most will get the idea with "45".

A 1960 one might have been close to where they swapped to 10000 series engines?

The supercharger might look like a GM but it is cast iron and made by Sweitzer - and heavy