6.300 rods in a 416 stroker

First thing to do is figure out if those are Mopar rods or Chevy rods. I just finished up a 427 inch small block using 6.200 long Chevy SB rods. That combination worked just fine and it had a longer 4.125 inch stroke in it. So the 6.300 rods will work on a 4.00 inch stroke in terms of length. The problem might be the size of the big end, especially if it is a Mopar rod and not a Chevy rod. The Chevy rods are smaller and take up less space around the crankcase and oil pump area.