I would think the long rod would use a shorter,lighter piston,resulting in a lighter rotating assembly, I would use a lighter rod with the lighter piston weight, I would also check to make sure clearancing is properly done with the longer rods. With the lighter pistons I would lighten the crank a lil bit,I would also use new rods as ya dont know how many cycles are on a used rod. A longer rod will use a lighter piston adding life to the rods. Finally, I would shoot for a 1.80 rod ratio, bad lil engine built on a budget.... voila