Head work
A "three angle valve job" refers to the seat angles cut into the seat surface in the head. Example: a lead cut of 15 degrees followed by a 30 degree seat angle (where the valve actually seals against) and a 60 degree cut to lead into the port. There are different angles depending on intake/exhaust valve. There are also 5 angle valve jobs. More angles cut in to aid in a smooth flow through the port and past the valve. Good valve machines cut these angles with special tooling that accomplishes this all at once. If you're heads still have the original valve guides in place, you need new guides. This is not a job you can do on the floor at home. You need specialized equipment to cut out the original guides and press in new ones, then size them to specification. Intake valve stem clearances usually run .0003 to .001 thousandth of an inch. .003 to .005 is the diameter of the human hair. So with a valve in place in the guide with NO valve spring, just pull open the valve right off the seat and try to wiggle it. If you can feel movement, most likely you need guides. I hope this helped. lotsa luck. Steve
