Timing question.

[Russ T. Fender]

When I removed the timing cover on my 30-U engine I found that at some point in its life the cam shaft gear was installed one tooth off.  I drove the car for more than 10 years with it that way.  My question is has anyone else encountered this.  I am wondering if it was done on purpose to get more advanced timing. I also found that two of my pistons were marked Chalmers Motor Company while the other two had the Chrysler logo on them.  I believe Chalmers was acquired by Chrysler after Chalmers merged with Maxwell and Chrysler rebadged the Maxwell line as Plymouth so I am assuming they were still using old stock as late as May 1930 when my car was built.  The pistons are standard size but it is possible that they were replaced at some point during the 42 years it was in regular service.  Does anyone know if they were using Chalmers piston in Plymouths from the factory as late as 1930.