It is a good thing that you asked. You don't want to give the Hemi bashers any ammo. We don't want to be hearing a bunch of stories: "I just beat a Hemi with my 327 Nova", my stock 340, etc..
So when you build a Hemi, you have to build a raging bull elephant, not a little baby elephant holding onto its mammas tail. You have a great start with the heads and the stroke. Now you need a big rompin' cam and a decent intake to wake it up!