Both Intake and Exh seats are a 45 degree. The all important Exh seat width should be a minimum of .080" wide , but no more then .100" wide. The Intake seat can be anywhere from .060" to .080" wide. These are the seat width specs for long long valve life, not nessarlly the best flow , but just make note that a full 75% of the heat a valve collects gets disapated thru the valve seat, not the valve stem! The minimum seat width that I use for max flow in conjunction with a 2 or 3 angle valve job is .050" for Intake valves and .070" for Exh valves. Also note that the narrower a seat you start out with on a new head the less valve jobs you will be able to do down the road to freshen things up!
