Originally Posted by snaparen
It is a snap ring, but made more like a key ring(similar to agd lvl 5 valves on the powertube) you have to get a pic under the start, pry that out of the groove and then pull that end and the rest of the ring will follow. I usually stick myself in the finger a few times with the pick before I get them out. I guess they require a little blood sacrifice.
And that youtube link above, that is a old "rope" style valve. They were used in 68 carbines only, but had problems and were replaced with the CVX valve, which was used in all the pro-carbs. The cvx was a drop-in upgrade for the 68 carbine, I think it latter became stock for the late models.
Yep this is what I have, an old rope valve.