Intake valves M271946

[Gav2504]

Quick question regarding intake valves. I've already rebuilt the bottom end.
I opted to re use the valves.in the head. Exhaust valves are fitted. I was grinding in the intake valves and noticed every single one has a slight wobble. So I'm replacing them all.
I've attempted to purchase a full set but have come across an issue. There are 2 different sizes and apparently they both fit. The length and valve head are identical but the valve stem diameter is either 6mm or 7mm. I've measured mine which are 6mm. I would imagine all original m271 valves will be the same.
My question to anyone in the know is have the 6mm one's been replaced with 7mm for some reason and will the 7mm versions fit? The spring cap opening is roughly 6.8mm
I'm baffled as to why both sizes are listed as being the right ones for my car.

 

[BlackC55]

What is your chassis number?

 

[Gav2504]

What is your chassis number?

No idea off the top of my head. I'll check But if it helps It's an 06 plate clk200 kompessor A209 with a m271940 engine but I'm replacing it with an m271946 out of an 07 plate c class. Chassis number of the c class is unknown.

 

[Gav2504]

Chassis number is WDB2094422T073053

 

[Gav2504]

I've just checked the old head and compared to new head. Both have 6mm valve stems but that's hardly surprising as they both have the same Code on them which is R2710161201