BIG Thank you to Dave the CAT expert! At the last FMCA rally, Dave read the codes on my C12 CAT engine. I got many pages of useful information. On his advice, I changed my RACOR primary fuel filter to a CAT filter set up. Also updated the line from the primary fuel filter to the fuel pump. I can say as others have said that the engine runs quieter and smoother.
Again, thank you Dave!