The speed pack pistons for the hemi are a 4032 alloy which is a higher silacone alloy. The benifits of that is it's cheap and because of the silacone content is more thermally stable. For this reason you can fit the pistons real tight for a forging (like 0.0025-0.003") so they won't irritate the knock sensors as much as pistons made from like a 2618 alloy. 4032 is more an OEM/mild performance alloy for pistons and normally isn't used in applications at much over about 500 crank HP. The reason for this is the alloy has a tendency to crystalize and fracture over time so it won't hold up for extended use at high power levels and as the engine gets older the material gets brittle. I think the JE's use a 2618 alloy on most of there pistons which is softer and less thermally stable so It will install more around 0.004-0.005" (not sure the exact spec on the JE Box forging) but it should be pretty close to that. The 2618 is more ductile and will take allot more of a beating without breaking. Or something like that.
if it makes you feel any better I blew up 6/8 piston rings before I changed mine. only problem is I didnt have time to wait a month for wisceo to make my pistons so I had to order mahle ones again. I hope I dont regret that down the road
yea my pistons broke on the top of the flat part. so if your looking down the cylinder you would see a circle with 2 spots missing metal. so my guess would be its the ring. I dont know the name for parts and so on so I can tell you right where it happened. but it didnt look like yours. I was missing a nice amount of the piston though
