Yes; you can see them without pulling the head, or even the rocker arms. Just need to remove the valve cover and get in close with magnification; they are tiny numbers!
The number is stamped around the end of the valve, just above the spring retainer. You have to get up close, and at least one of the valves should be in a position where you can read it.
The early (bad) '04 to mid/late '06 valves are stamped:
Intake:72377
Exhaust: 72524TK
In late '06, they implemented the improved valves, which are stamped:
Intake: 72377 C2
Exhaust: 75219 TK
In '08 they improved the strength a bit, and have the following numbers:
Intake:- 72377 T2
Exhaust:- 75219 T1K and
Note that a number starting with "72" on the exhaust is bad, starting with "75" is good.....
They didn't make the hollow valves for weight reasons. They used a concept called sodium-filled. The hollow cavity is filled with sodium metal and the sodium melts and conducts the heat away from the top of the valve better than regular valves. The new valves are made from Inconel which stands the heat better.
The number is stamped around the end of the valve, just above the spring retainer. You have to get up close, and at least one of the valves should be in a position where you can read it.
The early (bad) '04 to mid/late '06 valves are stamped:
Intake:72377
Exhaust: 72524TK
In late '06, they implemented the improved valves, which are stamped:
Intake: 72377 C2
Exhaust: 75219 TK
In '08 they improved the strength a bit, and have the following numbers:
Intake:- 72377 T2
Exhaust:- 75219 T1K and
Note that a number starting with "72" on the exhaust is bad, starting with "75" is good.....
They didn't make the hollow valves for weight reasons. They used a concept called sodium-filled. The hollow cavity is filled with sodium metal and the sodium melts and conducts the heat away from the top of the valve better than regular valves. The new valves are made from Inconel which stands the heat better.