cummins 'c' series big end ,u, bolts help

can someone suggest what to do about replacing the ,u, bolts on the big ends in a c160. i remember seeing a post about not using the old bolts because they stretch.
can you still get bearings and rings etc for a rebuild. i have two engines one has put a foot out of bed and the over has a linner split, i am hoping to build 1 good engine.
if anyone needs old parts i will have extras.
thanks

re c series cummins conrod u bolts- many c series engines had rod bearing failures due to hurried instillation or just ignorance! it is time consuming to do a bearing change on a c series but its not rocket science. the first step after installing new shells in the rod and cap is nip up the u bolts evenlly then align the rod to the cap, this is done by levering the rod to one side of the crank and then taping the cap i the same direction then insert a .008 feeler between the rod and the crank and see if it will grab under leverage if so repeat the process on the cap if the feeler grabs then the rod and cap are aligned! next step tensioning u bolts step 1 tension all nuts evenlly to 15 ft pound step 2 tension to 30 ft pounds step 3 back all nuts off 90 degrees then repeat steps 1 and 2 the reason for this is to[ bed in] the lock tab step 4 advance all nuts 60 degrees, step 5 set tension wrench to 38 ft pound and tension each nut , if the wrench clicks off at 38 ft pound the u bolt is servicable, if the nut contiues to turn the u bolt is stretched and u/s step6 if every thing is ok bend over the lock tabs on all 4 nuts! as i said time consuming but if you follow the manual and double check your work it will be ok - hurry it or take short cuts and you will kill the engine as for parts there gettin scarse federal mogul still were supplying bearings?????