E58 400 plus HP Dart sport build

4.7Light said
Little stuck on piston choice I dont want a hyperkinetic piston now. Builders really hate on them for breaking and I'm concerned as they were pretty vocal and it was multiple folks. I know a lot here use them but I'm going to error on caution regarding my kb107 and not buy. I need a stock weight piston forged if possible flattop valve relief. The ones I have seen look like I will have to rebalance and do a new converter and such for the combo. It's also about the fact it's my motor and I want to do it my way my choices if that makes any sense. Any suggestions on the piston choice still waiting to hear back on overbore and how much I may have to go.

From what I've read, a big reason people have problems with the KB hypers is they don't follow KB's requirements for ring gap. If you don't follow KB's recommendation, the top ring ends will but when the engine gets hot, the ring sticks in the bore, and then bang the top land on the piston breaks. Set the ring gap to what KB says and you shouldn't have any problems. That said, a nice set of Mahle's with rings is only about $100 more than a set of the KB 107's and a set of Total Seal gapless...
As for balancing, it's about $300 which might sound like a lot but isn't really a lot considering how much you pobably already have in the engine.