another rod option for the future on a standard 351w crank is to use the 400M length rod and the 302 piston. many locals running roundy rounds are doing this. seems to be the new ticket in the NW. not sure why but a builder in my area has a few setup like this.
You might want to check your information.
The 351M/400 rods are much longer than that and also use a much larger pin. If you bushed the rods, you could likely mill a ots 331 piston enough to be usable.
Scat does make a 6.125 H beam rod with standard Windsor sizing that allows you to substitute regular 302 pistons. Ford Racing used to offer a similar I beam rod.