I don't know what kind of tools you have, but you would get out cheaper to make your own steering box plates. All they are are two plates with 3 holes each, and three tubes to go between them. Doesn't really matter what they look like as you can put them wherever you want on the frame. I don't know anyone out your way that fabs stuff other than Rich, and I am not sure how far you are from him, but you could probably get someone local to make it for you cheaper than buying a 'kit'. But Bentup is the only company I know of that makes an actual kit for it. It is all pretty simple to make, the front hanger uses 9/16" bolts for the springs, and needs to be 31.5" center to center I think, and 34" outside to outside if I remember correctly. Go to toy4x4.net his design of front spring hanger looks good ans is easy to make if you can find someone close to you to make it.
And BTW, you might want 44044's to clear the 37's. I just put some on my truck that I bought from Patrick H, give me room for 35's I think, and ride better than the 7-leaf waggys. My stock waggy springs were sagging fairly bad, but they flexed reeeeallyyy good. Don't make the mistake I did with the steering box, push it as far forward, and vertical, don't angle it.