i keep a list of castings and where they are used, your was not on it, so i google searched a bit and compared the stamp markings to known samples. block casting 3733949 is listed in a few places as 1953-55 235 USA
reading between the lines, and i might be totally wrong here, it appears that this engine may have been from factory paired only with manual transmission vehicles and had solid lifters? but the engine was sold alone as a replacement engine with either solid or hydraulic lifters to at least 1957 according to one post someone made online that i can't find now.
also to make it more confusing for you... the stamp marks look a lot like the Canadian engine serials, the shape of the 6 looks like Canadian engine markings. USA 6 is not curved. also the fact that it has just 6 numbers and no letters at all, that's how many of my truck engine serials look like up in Canada. perhaps this block was made up in Canada years later in 1959?
lets see if others can shed light on the mystery. -s
