Hello All,
After some more digging on the Interwebby

I found this bit of information .... Accessed November 19, 2016 from,
http://www.canadianregister.co.uk/engine_serials.html
From 1938 through to 1940, truck engines had a 'T' 1st letter prefix, light commercial trucks had 'K' and some CMP trucks also used 'T' with 'R' for RHD. Australian exports had 'TRA'. 'AR' was used for 1940, 'WR' for 1940-1943, 'ZR' in 1941, 'XR' in 1941 ( FATs ) and at the end of CMP production, 'SR' in 1942, 'PR' from 1942-1944, and 'FR' from 1942-1944. 'X' was used post-war with GMC trucks.1945 models usually carried a 1944 code. . . . . The 2nd letter was usually an 'R' to indicate Right-Hand drive.
Another look at the website says ... "The 1st digit '2' was the year code i.e. 1942." So my engine PR3801619 was made in 1943.
So does this mean I have a Canadian made motor that was originally fitted to a CMP truck, then used as a donor motor which was later put into my truck sometime between 1943-44 - or shortly after?
Is there anyway to find out what factory in Canada produced my "PR" motor and what city the factory was located?
Either way
if the Army did an engine swap the original motor did not last very long!
If the Australian Army did do the engine swap would there be any records of what my truck's ARN might have been and handy information like the still elusive Chassis number?
If as the website suggests, once I get the engine running I will have to play the Canadian Anthem and christen the engine with Canada Dry
What other alcohol does Canada produce? I know Bundaberg where I live is the home of Bundaberg Rum...
Kind Regards
Lionel