To save a little change, if I can get away without boring all the better for money, just use a standard bore piston. Depends on how for in the hole the pistons are..... and what CC the heads will be. IF pushed in a corner, I'll use the magnum heads for compression. I don't want to break the bank on this build. Cost is a driving factor. Last time I threw under 500 at a 318. It did exactly what I built it to do, and still does. This time I'd like to stay under 1500. We'll see.