the problem isn't really making sure they are round...the problem is the amount of weight that is being thrown around!! the compression stroke is pushing a lot of weight up. this will over the long run, cause the crank end of the rod to elongate and an unbelievable amount of force on the wrist pin...then you have ignition and the rod is getting slammed down, elongating the hole even more and jerking the wrist pin down.... this is going to cause some serious problems! if your going to be using a big block rod, then you might want to consider a better wrist pin too....I saw first hand what the forces on a stock rod/piston and what a good rod/piston combo looks like after running at 9K.....it wasn't pretty!!!