I would imagine it would work. I don't have that servo or a Savage 4.6 but most servo's (except micro, large scale, and probably special flight types) are roughly the same size, maybe a hundreth different here or there but generally about the same.
cool deal. i'll have a spair one for the steering. these are good high-torque didgital servos right? which radio should i get fm or am? will i have to do anything to get them to work with the radio i get?
Those are hi-speed but not considered to be hi-torque. I think it would be a much better throttle/brake servo rather than steering. It's really fast but not quite as strong as some of the other Digital hi-toque servo's. but I say if that's what you got... use it. If it seems like it's not strong enough then upgrade to an s9350 (assuming you're happy with Futaba).