Hi Jason, my guess is it is a pilot or it could well be out of a pommy truck (thames) or the like, although i'm no expert on these things. I've have spent a bit of time trying to identify it any better, thats why i was curious when you posted your engine no, as it doesn't marry up with any either yankee or canadian models. The best I have come up with from speaking to different people is they seemed to be made up of various parts left over from post war, sort of based on the late '37 early'38 american motor. Keith is correct 3 1/16" bore, I put rings and bearings in it and had a bit of a hard time finding suitable bits as it was .045" over(which is aparently a common size for them)and the big end bearings are different to everything else. The use a bearing that is flanged on one side only and is a individual insert type with a lock tang, same as the BA motors not the fully floaters (ie two rods on the one wide bearing).
You could try a company called Yesteryear ford in Burgess rd Bayswater Vic as he was the only place that I had any success.
Either way if its a runner it'll get you going till you can find a suitable replacement with time and dollars, it wont give you wiplash but it gets you going mine will cruise on the flat comfy at about 75km or 80 if you want to push it along a little
it's done 2500 miles now in the last 12 months and are currently building a replacement 99 block as dollars become available
Water pumps are the same as car ones single pulley you can get the later type with a sealed bearing instead of a bush, couldn't see any reason why you couldn't use the truck twin pulley type, I didn't in my case as I run an alternator and drive the fan of the extra front pulley on the crank ( didn't like the idea of that big heavy steel fan of the little alternator shaft) although it probably wouldn't fail.