Here's another thing I have learned. The stock block is on the weak side, but it will be fine for an N/A combination. A stock block 347 can handle a reasonable power adder as well. Say you are committed to that 347 stroker engine. You build a stock block N/A engine today. It's going to make 400hp easily with the right set of heads, cam, etc. That's not an issue. The cast cranks are good to 500hp. A good forged rotating assembly is in the range of $2k. You spend the money on the forged rotating assembly now. If you later decided you want to add a serious power adder,, you take the engine back out and put that rotating assembly in a 4 bolt block. You lose a little money in machining two blocks, but it isn't much in the long run. The big money is in the rotating assembly, and the heads.