Dome top pistons in a FE Series Ford engine will generally provide compression ratios in the 12.5:1 to 13.7:1, depending on engine size and cylinder heads, range which makes them a good option for engines with competition applications. Valve reliefs are configured to work with most types of standard and aluminum cylinder heads and will normally fit camshafts to well over .600 valve lift. The top ring is spec'ed at .280 down to clear relieved blocks.