Any one know how far you can safely cut a 351w crank. The one in my coupe was cut to 10 under on the rods, and 20 under on the mains. I am doing anouther rebuild on it and there is a little scoring.[not a lot, tiny bit] can this be cut more? I know the mains are huge for the size of the motor, but is 30 under to much? Or should I be looking for a new crank.