so i'm rebuilding my original 1970 340

i want to have the lightest rotating assembly possible , forged crank h beam or I beam rods and forged pistons , don't want a speed demon more for highway driving ,maybe a road course once in a while \guess i'm going to go roller cam on this build going to use the hughes rockers and morel lifters . not sure which heads and cam to get
Who makes the lightest crank rods and pistons these days also want the best gas mileage possible , i got around 22 mpg with my last 340 but that was stolen
Open to any and all suggestions
So you are going to go with a roller cam and expensive lifters and rockers, and you plan to hit road courses (which require plenty of power) AND you want 22 MPG/ Good luck with that!!!!!!!