Howard's or Lunati

With what I'm wanting to do with the 318, could I use a SP cam, something like a comp 268*? Howards has a cam I like it's specs are .506 / 267* 220*@0.050. LSA 108* I don't know the icl of this cam. RPM is 1,800- 5,800. Does this cam have to much duration at 0.050"? Cylinder heads: Would I be better off buying a set of bare speedmaster cylinder heads? Would the 170cc intake runner size kill off low to midrange torque? Do I really need a edelbrock performer rpm intake manifold for what I'm wanting to get from the 318? I doubt very seriously if the 318 will ever run over 4,800 rpm's. It's strictly a cruiser. I figured that the 318 would need gone over anyway so I thought that I would add some extra zip to it. I plan on 3.55's. Is there anything that I can do to the transmission to help over all response of the car? Carburetor: can I use a 500 or a 600 cfm edelbrock carburetor? I'm hoping to be able to start gathering parts here soon and I don't want to have to buy a part twice.