I check in some of my old PHILCO SERVICE manuals This is for a 1951. P5106 is a Mopar 812 ,D5107 is Mopar 813 ,C5109 is a Mopar 815,C5110 is a Mopar 816 C5111 is a Mopar 817,and C5112 is a Mopar 818
They are OME for Plymouth,Dodge and Chrsyler, apparently the first two numbers are the year, I have worked on dozen of these and never knew this ,learn something new !
If you can get me a picture I can ID it for you