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ok so now i'm lost......4 to 5 angle grind is bad for heat dissipation and full radius is best or vise a versa? and porting, sort of polishing and 4 to 5 angle grind are to get it off boost faster? or atleast that was my thought and reason for doing so that and a little more cfm capable flow from head.
also been looking at these.....http://www.flowperformance.com/system.htmlthoughts? not looking for peak cfm just consistent cfm reading so i can flow match and was considering doing so with intake on?
On a turbo engine the width of the 45* valve seat is crucial to cooling the head of the exhaust valve. IMO,it should be in the area of .100 and if running boatloads of boost a bit wider. If performance off boost or what is the equivalent of a normally aspirated engine is important to you then a radiusing of the 15*/30* angle top cuts and a radiusing of the 60*/75* bottom cuts will show slight gains usually but a quality 5 angle configuration is basically the same for all practical purposes. The 45* seat is left flat. On a pure drag engine some head builders will radius the 45* seat as well . The radius seat seals very well due to the high PSI load in the very narrow contact band but will transfer very little heat from the valve head which isn't much of a concern for the very short operating time of a drag engine. Endurance heads will never have fully radiused seats for that reason. The exhaust valve would be begging to fail. Pretty much the same applies to the intake valve.