Real Estate Profit Sharing Agreement

I'm looking to get a legally binding contract drawn up in regards to a real estate project in the USA. I'll be buying the land, but entering into an agreement with a local home builder. He will have sole builder rights to that land. We provide the capital for the land, and the home construction. He provides the day to day management, contractors, labor and ensure the sale of each home. We then split the profits 70% to us, 30% to the builder. The provided agreement does not protect our interests. We need one more complete that outlines and protects our investment in the project.