I couldn't find any except for a custom fiberglass stock at $595 from MPI! And everyone is sold out of the wood stocks.
If I were you I'd inlet or drill a hole for a piece of brass rod or 2 (available at hardware stores ) running across the crack then epoxy it and the crack. Lots of info on stock repair in this forum. The exact location and rod size depend on stock geometry and crack location.
The older Ruger 44 Carbines need full power ammo to function. A lot of 44 ammo is wimped down for revolvers and function will be iffy with that, causing lots of jams.