Is the 13" flywheel that comes with a SB ConOFE a direct fit of of a newer cummins or is it a modified flywheel from an original? The reason I ask is because I got a OFE disc and pressure plate w/o a flywheel cheap but need to come up with a flywheel to make it work on my 98. Any thoughts? Can I run down to Cummins and get one or do I go through South Bend?