I would agree with 5shot's post, 50-55 ft/lbs of
KE is a good guideline for using mechanicals. I'd
recommend the Rocket Steelhead's as I've seen
some great results with these shot from proper
setups. Both the 100 gr.(1 1/8" cut) and the 125
gr.(1 1/4" cut) have chisel tips and 3 blades.

Here is a link to some broadhead test results:
http://www.american-hunter.com/broad...dhead_test.htm

Good Luck
TB