Valve stem length for 70-71 15x7 rallye wheels?

Looking to confirm the valve stem length used with the 70-71 15x7 2944390 rallye wheels? I know they take the 1/2" extensions part # 2660315....just not sure on the actual valve stem length? Also, when the extension is installed is the connection to valve stem below the surface of the trim ring? Thanks in advance. Joe

I don't know the technical answer to your question but in my case always install the shortest stem I can buy and then use my factory 1/2" valve stem extensions.
Ron

So does that mean to add air the trim ring comes off?

Thanks Ron! I am thinking 1 1/4" valve stem is correct or very close. Joe

no. the air is added through the extension.
if the 1/2" extension is too cumbersome to add air, a fellow can always carry a longer, metal stem extension to make things easier. then replace the correct 1/2" extension when done.

this is supposed to be correct

Thanks to all that replied. Looks like the 1 1/4" stem is likely correct.

I wonder if the reason for the short valve stem & plastic cap extensions was to keep the rubber stem below the trim ring so it couldn't get cut @ higher speeds by the edge of the trim ring valve stem opening ?