Proper contract for Builder + Investor partnering to build home

[Victoria S.]

A home builder is partnering with an investor to build a spec home. Investor will be financing the construction; home builder will perform the work. They plan to split the profit after the sale. What is the best way to structure the deal to protect both parties? Should they put 50/50 down on the land and be 50/50 on the title? Are there specific clauses to include in the contract for this type of arrangement?