Investor Contract agreement - Private investor

Hi,  I am a GC here in Florida. I have a private investor who wants to give me cash to buy a lot, build a spec home and sell it for him.

I am in the need of a contract for him that will secure his cash so he knows it wont be used for anything else than that.  Also something that can guarantee him the sell of the property. Any feedback would be greatly appreciated it. ..

Just so you understand better the situation. I already bought the lot with my own money. But I need money to build the home.  I will charge him the cost of construction plus my fee. Let me know if you guys have a contract that you use. Thanks.