How much boost are you thinking of? If you are going beyond the range of around 7-8 lbs of boost, then I would be looking at a strengthened bottom end. And IMHO, stock type cast pistons are out of the question; you might get by with them for a very low boost use, but maybe not. I have run both forged and hypereutectics in rally 4 bangers with 14-15 lbs boost with no problems, but forged is the preferred type.
BTW, 318willrun's comment on the piston tops is what made me look more closely. So give him the credit. And I sure would like to know what is up with those 2 pistons, so let us know when you find out.
