Can I use an x valve on off in a classic valve?

[halB]

I seem to remember that you can get slight reactivity with an rt on off pin. What about just an x valve on off with a classic pin?

[athomas]

Yes you can use a retro on-off assembly in a classic valve. It is a drop in replacement. However, you still won't get much reactivity. The classic uses regulated air to push the on-off pin unlike the retro valve that uses tank output pressure. The classic pin won't fit the X-valve on-off assembly.