T.M. - Have you tried to test the armature using "Steps 1 and 2" as shown on
Page 12-22 of the 1948-51 Chevy Truck Shop manual.
Done with a multimeter (deosn't require the growler), you can at least get a preliminary indication if the armature is grounded or not.
A little digging in some Chevy Master Parts Books shows the armature was listed under two different GM#s over the years:
GM# 1867897 Armature, 6V 1938-50 for ALL 6 cylinders
GM# 1917855 Armature, 6V 1938-55.1 for ALL 6 cylinders (this number became active in 1951, replacing the original part number)
This armature is actually the same one used in 6V GMC and many GM passenger car 6V application too.
A quick scan through the web located just one supposedly
Vintage 1940 1950 NOS Delco Remy Chevrolet GM Starter Motor Armature 1917855, but it looks to be in pretty rough condition. I also found a listing for a
5040-1700 Reman Armature for Delco 10MT Starters 6V CW Straight Spline which would provide you a warrantied replacement armature if that's the way you want to go.
Hope this is of some help answering your questions.
