I am just freshening this one up........my 340 was the block I had done at a shop. Cha-ching! This 383 ran well, and only had 69k on it, and all the parts show it so far. I am going to try the copper spray sealer, I have been reading it works well. I am going to go with the steel shim, for a lot of reasons, mostly to squeeze as much compression as I can using the original pistons. Plus I want to try something different, I have never done it the "old way," and I want to.