Dish top pistons in a Ford 351 to 427 engine will generally provide compression ratios in the 9.0 1 range which makes them a good option for engines with aluminum heads and larger than stock camshafts. 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. Some are available with a dual intake valve relief for use with standard as well as Twisted Wedge cylinder heads.