BIG VALVES AND SEATSThese Stainless steel valves and seats are perfect for converting a stock Briggs Animal, LO 206 or World Formula head to a Big Valve Head. They have the same dimensions as the stock valves except for the head size. The intake valve has a 1. 250" head and a 1 4" valve stem and the keeper groove is in the proper location to give you the correct valve spring pressure. The exhaust valve head is 1. 125" with a 1 4" valve stem. The valve face is ground at a