Watch out with the open chamber, dished piston, 9.5:1, carbs, and pump gas. There is far more power to be had at 8.5-8.8 running good timing, and you get to keep your pistons. The open chamber/dished piston combo is notorious for not liking much compression - especially without the aid of 02 sensors and fuel and timing control. If you are racing and can run good gas go right ahead, but I would caution if your trying to do it with a small cam and 93 octane.