Best piston for street/strip 340?

It's about lifespan and power output. Pushing heavier parts around takes more power, the quality control is not as precise which will affect output, and controlling the extra mass is more stress on the rod, crank, and block. So it comes down to what can do the job required for the least money, and the least weight. At least for me that's usually how I decide what to use.
For the OP - I'd run the KB hypers unless there is not a cost issue in which case any modern forging would be fine. I'd avoid the oldschool because there's a lot better stuff around for a little more money.