Hi,  I'm buying a '50 or '51 (owner doesn't know which) barndoor bus.  The
engine is gone and the trans is shot.  Does anyone know what size engine came
in a '50 or '51? 
      I have found what looks to be a older engine but can't figure out
anything from the code.  Here it is:  A 90 (stamped in)  and 1458006 (cast
in).  On the right side behind the oil filler tube it has an "M" stamped into
it.  On the left side it has an enlongated circle with three smaller circles,
each containing a number, all three in a row within the larger elongated
circle.  These are the numbers: 7   6   36 
this was all cast in, not stamped.   If anyone can tell me anything about
this engine or what size the bus is supposed to have, please let me know.
                                                   Thanks,
                                                           Eric