I have a Savage long action that started life as a 308. I've had it configured in many different calibers, from 223 up to 338 Edge.
If it is an older stagger feed you may just have to change the bolt head. The box and follower may work just fine with none or a little tweaking.
If it is a newer centerfeed, then you'll need a bolt head and magnum mag box to make it happy.