Intake & exhaust valves sizes!!
Intake & exhaust valves for 2.5L
Intake Valve Head Diameter (mm) 32.0mm
Exhaust Valve Head Diameter (mm) 26.0mm
Intake & exhaust valves for 3.0L
Intake Valve Head Diameter (mm) 35.0mm
Exhaust Valve Head Diameter (mm) 30.0mm
4.6L DOHC
Intake Valve Head Diameter (mm) 37.0mm
Exhaust Valve Head Diameter (mm) 30.0mm
4.6L SOHC
Intake Valve Head Diameter (mm) 46.8mm
Exhausst Valve Head Diameter (mm) 35.9mm
I think an increase too a 37mm on the 3.0L head would be a good idea. While cleaning up some the castings and making the dome in the head cleaner.
Both valves have the same length and valve stem bar diameter.