Why is it then that NAPA lists 30mm cylinders as stock for the back of my 97 3500?

 

Good question, I need to do the rear shoes and need a rear drum. I wanted to see about the 3500 drums and shoes. Well Napa had the same part number for the 2500 and 3500 drums and shoes. cool, but $116 for a drum, $77 for their primo shoes, gotta save a little more $$ first.

 

The guys behind the counter don't know what they're talking about. Go to http://www.napaonline.com/ and enter your truck info, they will be 27mm (1-1/16")
30mm is 1-3/16"