59T was used by Ford as a model and as a part number prefix for postwar large truck stuff...also, the number you show is WAY high, like about 10 times production of early type 239's, so none of that makes any sense at all! A V8 '48 Ford should have something about like *899A-number in the 2 million range*...your number would still be too high if cut back to the right order of magnitude!
I would go straight to the bell housing number, in hope that car has its original transmission and so its proper number there.
There is actually an access to see that...if you look at the top center of the toeboard under the edge of your rug, you should see a long oval tab cut out on three sides. If you bend that up you should be looking at the serial pad. If you are lucky it may be clean enough to read without serious work.
Does car have a title with a number on it?? It is conceivable that this is some sort of state assigned number for a car that lost its original paperwork.
. I can not seem to locate any reference to the 59T. Also their are no stars before or after the number. Thank you for any help.