Yes, the same 235 engine in the same year.

Same 10mm plugs on all 216/235 engines (all Chevrolet vehicles) through 1948. AC 104 (good luck finding that specific part number).

Have you checked Rockauto.com? They have the wrong size/ part for a 48 235, but the correct AC plug listed for the 216.

An R43 (14mm or AC 44-5 14mm) is simply the wrong size for any pre1949 216/235. At least, that is what the spec manuals show - see links below.

If your head uses a 14mm plug, you might have a later head on it?

http://www.rockauto.com/m/mobilecatalog.php?carcode=1486745&parttype=7212
http://chevy.oldcarmanualproject.com/chevyresto/4895.htm
http://chevy.oldcarmanualproject.com/chevyresto/4990.htm

Tim
1954Advance-Design.com
1954 3106 Carryall Suburban
1954 3104 5-window pickup w/Hydra-Matic
The 216 and early 235 engines are not "splash oilers" -- this is a splash oiler.