Went thru this on another forum...this is what was found or lack of.. (Any part number that is CAST into the iron housing or CAST into the aluminum side cover, is exactly that -- saginaw in house casting number. It will not help you in any way to find your particular steering gear. Starting around 1969 Saginaw started ink stamping a two letter code on the side cover and/or the aluminum end plug. The two letter code was used at the GM assembly plants to keep different part number gears separate. (It was much easier to glance at a two letter alpha code than a 8 digit part number.) your 1 / 236 is julian date code 71 or 81 of Aug 24....saginaw in house stamp

Unfortunately, the ink stamp numbers were never considered to be a thirty year identification.)