Decoding the Dodge Parts Book

[DaveVA78Chieftain]

While this information is located on the first page of the Dodge Parts Book, I suspect it gets missed.  Because of the
coding used in the Dodge MH Parts maual, it can be confusing at times to determine which part number you need. You not only need the year model, you need the chassis key code from the first page of the parts manual.  Dodge did things like referring to the M375 chassis as M4 (If you look at the brake overhaul pictures they refer to a 72 M400; it's actually a M375).
The following table is a condensed version of the key code information.


 
   
   
   
   
   
   
   
   
   

Chassis Model		1969 - 1972		1973 - 1974		1975 - Up
M300		M3		-------		M3
M375		M4		-------		-------
RM300		-------		R3 (M300)		-------
RM350		-------		R4 (M400)		-------
RM400		-------		R5 (M500)		-------
M400		-------		-------		M4
M500		-------		-------		M5
M600		-------		-------		M6

You may notice that for years 1973-74 that
RM300 = R3 = M300
RM350 = R4 = M400
RM400 = R5 = M500
Per the 1975 Chassis Manual Supplement, Dodge made the decision to use only the model designations
M300
M400
M500
M600 (76 and later)
Additionally, Dodge decided to make this definition retroactive back to 1973.
So if you have a 75 M400 Chassis, you can use 95% of the RM350 information in a 73/74 Chassis Manual.
The other place this mapping is useful is for tracking down parts.  Most parts houses (like Bendix) use the
remapped chassis information in their documentation.  If you have a 73 RM400, then you want to look for
1973 M500 parts.  If you have a 1969-72 M375, then you will most likely find it listed as a M400.

Dave