The IC825 from Keith Black will make it happen. It will be .045" in the hole at TDC with the 440 rod and 3.380 400 stroke and is made for the 4.342" bore. That is a off the shelf piston for a 468 cube motor based off the 400. They are a forged piston. Summit has um for 471 bucks.
http://www.summitracing.com/parts/UEM-IC825-040/
