I have a 1986 industrial cummins 5.9 12 valve eng..getting oil in water and water in oil..pulled down to rebuild but closes place to have checked for cracks is 260 miles so found block on line that only has 76000 miles and was taken to machine shop and hot ranked and all measurements checked and is good..got it for only $300 more then what going cost me to have mine checked so got it....seller said all my parts will fit the new BblOCK and I double checked with person that sold me all the new rebuild parts and he agreed with seller that I could use the new BLOCK..here is my quest to everyone..on my old block the cam bearing was in front of engine..on the new BLOCK the cam bearing is in REAR of block...is this a issue?can I still use the new BLOCK ?