440 what am I missing here?

Can't go wrong with that advice, AndyF has already ran all this stuff on the dyno and on the street for the rest of us. Do what he says and be happy. I have to agree with PRH on the stroker deal. It's unfortunate that you you didn't come here beforehand for advice. For about the same outlay as the new crank and pistons you could have gotten a 4.15 inch or longer stoke along with pistons to match. Nothing like an extra 56 cubic inches or more with longer rods and lighter pistons to bring out the best in a 440. The extra cubes would also tune down the cam that came with the top end kit.