Hi Tolley,
Going from memory, so there maybe the odd variation or exception, but diesels in 40s are fairly straight forward and also ignoring prior and post models:
Diesel 40s did not start until 1975 and used variations on the B series engines - B, 2B and 3B mostly with 4 speed boxes but late ones had 5 speed. These models all had the prefix BJ -40; 42 (12 volt primarily for Oz); 43 slightly longer as was 44; 45 was a pick up or troopy; 46 may have been the extra long 45 (need to check that)
The 47 had the H engine(designated HJ47) and was either a pick up or a troopy and, I think later ones had the 2H or possibly the turbo version. Most of these went to Oz and were 12 volt.
There were variations made in S America some using non-Toyota engines.
I will check these but I'm sure others will correct my mistakes and errors.
40s were not imported to the UK officially as quotas were in force that restricted the volume of imports to protect UK vehicle manufacturing including LR.
But loads went to Europe - actually many were completed in a Portugese facility but obviously they are all LHD.
USA never officially had diesel 40s but Canada did.
Most every other had diesel 40s but there only a few countries are RHD
2H engines were primarily used in the 60 series through the 80s.
B series (3 litre inline 4) and 2H engines (4L inline 6) are old style engineering but are ultra reliable, easy to maintain but not fast or high revving - 'million mile' engines.
You seem concerned about having a LHD, but with these engines it could be years before you overtake anything that isn't parked!!!!!
Personally I have never found LHD a problem, although for the last 8 years I've lived in a LHD country but for the 9 years before it was with us in the UK.
Hope this helps.
Regards,
Rodger