how large is the 3L valve?

2.5 valve head diameter is 1.26 in intake, and 1.02 exh

i dont know the metric equation for that im too lazy to figure it out. how big are the 3L valves?

1998 CSVT NX stage 1 ford EFI kit MSD dis-4 B&M short throw K&N short ram intake Fsvt Euro 17's Trubendz 2.5" exhaust Spec stage 3 249.9 HP 258.2 TRQ clutch slipping the whole time