I'm not picky between the 350 and the 383, but ditto for everything else adfishe mentions. You also want to make sure your machine shop uses torque plates when your block is bored and honed. You will want to use moly rings, preferably plasma moly--it is more able to resist detonation damage. When you pick your cam, pick it for your vehicle combination (car weight, gear ratio, trans. type., etc.) and be honest with yourself about how you are going to drive it. It is better to undercam a little than to overcam a lot!
If you have more specific questions, feel free to PM or email me.