when i said the heads were garbage, i saw the specs and saw the cam then the hp/tq output an just what the previous poster said it doesn't make sense, they either made a typo, or those heads flow like crap, which honestly i would say the heads flow like crap, you heads will seriously depict how much power your motor makes
i would look for a 350 with no more than a .030 over bore, that way it could still be safely bored again, vortec heads, they are something that gm got very right, with the heavy full size car that you have i might even look into building a 383, it would cost pretty much the same as building a 350, but you get a slight hp increase but the real advantage is you get a nice tq increase at a lower rpm typicaly, cant recomend cam cause i would need to know more about the car, trans, gears, size tires, over all expected use, compression ration- bla, bla, bla