RE: Best Mech. Head.
With that much KE you really want a big cutting diameter. I have about 64 KE and shoot 100 grain Wasp Jackhammer (1 3/4" cut dia) It blasts through easily acheiving full pass throughs (even through bone) and bleeds more than any deer I've shot with a shotgun slug! This head is not for everyone! You need high KE! You have it and the nice thing is tracking is hardly an issue. They go down quickly!
Good Luck!
PRACTICE....PRACTICE....PRACTICE......SUCCESS!