You need to check with Cary.
6SN7 has @ least double the heater specs (VS the 6922) and the gains are different.
Not a 6SN7 fan myself, but it's been almost 20 years since I've auditioned tube gear (things change).
DeKay
6sn7 to 6922 adapter: good idea or bad idea?
I was messing around on tubedepots website, and when I put in 6sn7 as a serach enginge, these adapters came up to put into a 6922 socket so the 6SN7 could be used.
I would be using a pair of them in front of a Cary v12 (Cary calls them the "driver + input" tubes). There is plent of room on the amp where those tubes would be going. I have several pairs of tested good vintage 6SN7s I could roll in those sockets, and that's why the adapters caught my interest.