The rod journals on a 401 crank are 2.249-inches in diameter and the rod is 5.858 inches long. When you take material off the crank journal, you reduce the size of bearing surface and consequently, the size of the big end of the rod. Fortuatly, you can buy 6-inch rods with either a 1.88-inch. 2.00 inch, or 2.100-inch journal size with a common wrist pin size. As an example, if we ground a 2.249-inch journal to 1.88, the new stroke would be 4.04 inches ((2.249-1.88=0.369) + 3.69 = 4.04)). The new engine size would be 448 inches with a 0.040 overbore. Using the 1.25 hp per cubic inch calculation, the engine should make 560 hp. Sound good?