How good is the new Hemi, REALLY?

I wouldn't worry about component strength too much. I have a 6.1 in a 1969 Dart GTS and although I haven't run the car at the track, I have run it pretty hard elsewhere. These engines are a jewel of engineering. They've removed weight where it served no purpose, but left it or added where it would be of advantage. The machine work is beautiful and precise. The blocks are certainly not weak. Indy Cylinder Head is pounding these blocks hard in development programs every day, with no change other than billet main caps. As to the statement that "the rods are the weak link" ; every engine has a weak link. That does not mean that the rods are weak. Powdered metal technolgy is well established and accepted in O.E.M. performance applications. GM has used it in the LS series engines for years with high rates of reliability. On tne other hand, no cast piston should be run much higher than 6500 on a regular basis. If you are planning to RPM this engine, then yes, 4340 rods and forged pistons, for certain; but that is no different than a 340, 360 or any big block engine. The real story on these engines is the heads. There is nothing like these heads on any production small block of any make. 368 cfm @ .600! Power like you cannot believe. Torque curve as flat as Kansas. Hope this helps you sleep better. Good luck with your new ride.