L., first of all, bless your heart! Your candor demonstrates your honest desire to help your son.
Sometimes I think that our society and the way we live our lives has taken a lot of activities out of our daily lives that used to be a good vehicle for boys and their natural agressiveness. Years ago, many boys had chores on the farm, or wide open spaces to run and play. We live our lives very differently now, and yet a boy's need to RUN and YELL and BE A BOY has not changed.
I was raised with THREE SISTERS - NO BROTHERS - and am now a mom (newly single) to three boys, 15, 8, and 6. What started as anger in my oldest only got WORSE when his dad and I divorced. There were days where episodes with him left me trembling and afraid.
AS HARD AS IT SOUNDS, I made a valiant effort to REMOVE MYSELF EMOTIONALLY from the outbursts. I would quietly say, "I love you and want to hear what you say, but if you use that tone of voice, or talk over me, I will not listen." At other times, I waited as long to respond to him as it took him to obey me when I asked something of him.
Once I just responded like he responded to me . . . "WAit, I'm doing something" or similar phrases, and would not answer him directly for about 1/2 hour. It drove him crazy, but it made a point.
I also took stock of our relationship. I was NOT spending much time AT ALL with just him. The younger boys need me more and were getting the lion's share of my time. I made time just for us - like watching a movie to "old" for the younger ones, or just talking - and would say to his brothers, "Please do something else for a while, I am spending time with your brother."
I also got him involved with me in the kitchen, and would include him in things that I used to have his dad do . . like hang a picture on the wall, or say, "I need some muscle - can I borrow you for a few minutes?" He really responds to comments like that.
Keep saying that you love him - keep hanging in there. This too shall pass! Of course, seeking professional help is always a good idea if you feel like you need it. I would check at Second Baptist Church. Their pastoral ministries staff is wonderful.
Good luck!