It's a little over seven thousand feet.  It's a good pull from Sula.  They realigned the road about 10 years ago and somewhat straightened it out but there's only so much you can do when getting from point A to B with a needed elevation gain, ridges, draws and creeks in between.  You will not set any new world land speed record pulling a trailer up or down that pass.  Watch for bicyclists too.  It's a popular bike route and some are very militant(or stupid) with the attitude that "I'm entitled to the whole road" which they are but common sense would tell me anyway that if I were peddling a bicycle up that grade, I would stay on the shoulder and not ride 5 abreast on a blind curve.  It's best to not get them stuck in your fan belt.  Is Salmon the destination or just a portion of the trip?