6.300 rods in a 416 stroker

I'm not sure on the brand. What are the bearings in them? A 3.31 stroke small block running them could use a much lighter piston and be more torquey. That's a good idea and not a cheap build, but it makes them IMO useless for the 4" crank build. If you're Pro Touring you don't want all torque, you might want to run on pump fuel, and you'll want a piston that is stable in the bore at high rpm. These rods will IMO hurt all of that with a 4" stroke. For what you're doing, the std length rod (I'd suggest a K1 I beam) and Callies chevy pin forged crank are the way to go. I have one I did about five years ago that makes 500hp on CA pump fuel with the 6bbl induction. With an RPM an 950 carb it went 540hp. It's been daily driven "spiritedly" since then with a street solid roller. Touring is a balance of horsepower, torque, reliability, and longevity. I dont think 1.3" pistons are the best idea.