1970 Pontiac 350 cam?

cheaper to buy a much later low mileage engine with a bigger capacity from a wreckers a 400 or a 455 or similar but if you want to keep it genuine you may have trouble getting parts for a motor that old, you generally do not need new pistons, special oil control rings will do the job , the same with valves, it's the guides that wear and the springs, the stock cams can be reground to a better profile at an engineers all of these will save money, then just replace the bearing shells and you are good to go