Thanks all for the input. I have decided to go with the CW 4.315 crank, since the actual performance may not improve a lot with 30 more cubes on an already head limited motor. Also the center weights MAY contribute to better ring seal, and less stress on the block, since the rods i have for the 580 are about 70 grams heavier, which on top of no center weights would up the stress. Wish me luck😀 !