T140V is the model: Bonneville. (T was 'triumph', I think; 140 was an outgrowth of earlier systems of listing top-speeds, which started with more realistic T90 and T100, I think, and 'V' meant 5-speed, when there was still an option of getting a 4-speed gearbox in '71 or maybe '72.)
EH means it was built in May (E) of 1973 (H), per the table listed in the service manuals. I don't know if they were already doing '74 model year designs in May; someone else will have more knowledge, but I would have assumed it was a 1973. Check the engine number to see if it matches - it should be stamped into the cases just below the cylinders on the left-hand side.
It's a nice-looking bike. Cheers to whoever put those fuel filters on there.
Last edited by therabbithole; 11-15-2012 at 12:09 PM.