Trying to look up exhaust bridges for my 3zj. It says contact dealer. Call dealer and they claim 7c-0048 is supersede to 7c-0049. when I look at other 3zj serial numbers it gives me a choice of the 7c-0049 as well as 101-1818. The 7c-0049 is 71 bucks now but I can find several of the 101-1818 on ebay in genuine Cat and aftermarket for considerably less. When you just reference the 101-1818 on google it shows to b for 3406b and c models.Very little info on 7c-0049 fro google search . Cat parts online shows the intake as 101-1816 for my engine as well as the others I checked. Are there really several different exhaust bridges for these b and c engines? Just trying to freshen things up a bit . About 900 bucks through Cat or get oem for under 350 to change them all. I watch for stuff I don't need right this minute but do feel should be replaced, in effort to save a few bucks. Thanks. I figured one of you few remaining Cat mechanical gurus might know what I am dealing with off the top of your head.