Jay,
If you still want to know what engine you have, either post the number that is pressed into the block to the rear of the distributor or post the block casting code (I think it is behind the upper right of the starter - maybe someone else can give the location).
The valve cover is from a 59-62 passenger car but it could have been placed on any 54-62 235/261. The 54-62 side cover (push-rod cover) on 235s/261s did not extend over the spark plugs or above the block (it also did not extend above the block on 50-53 235s but yours is not an older 235).
As stated by 4ontheFloor, a 58-62 261 would have 1/2" NPT holes for an oil filter. Can you get us a clearer/closer picture of the oil line holes at the lower right of the manifold side of the block?
The engine color is not a good indicator because many people re-painted 216/235/261 engines that passenger-car blue color (most 261 were green but some were yellow).
Those Rochester carbs (which I like for originality) are jokingly called "leak-chesters" because they commonly leaked at the top-to-bottom joint. There are other things that can cause leaks - it looks like your might also have worn holes where the throttle valve pivots in the body.
Nice looking truck. That engine and carb set-up is a nice conversation piece and far more interesting than putting a modern engine in that engine bay.
Tim
