Unless someone has screwed with your stock stuff, it should actually be fine. If the dowels have wear on them, you replace them. To check the run out, use a dial, with a magnet, install it on the crank register, spin untill you have it centered up, then check on the bell housing hole center. I also believe you can go as much as .009 for max if I recall. But in most cases, 99% of the time most everyone just installs and has no issues. It's when you have miss mached parts, abused parts, or worn parts that puts you into a dilema. The receptor holes in the bell housing needs to be in good shape is all , along with good dowels.