340 build

If you can swing some lighter KB hyper pistons that would be the way to go. Lighter pistons allow engine to rev faster resulting in a quicker car. Lighter pistons also reduce stress on rods, crank, and bearings. And you can get that compression up to where you need it. You would have to get it all balanced. Stock 340 pistons are super super heavy because of their size so lighter pistons make a huge difference in a 340 build. I don't know what your budget is though.