71-1-321. Deeds of trust and trust deeds not invalidated. The Small Tract Financing Act of Montana does not invalidate or preclude the use in this state of instruments, sometimes denominated deeds of trust, trust deeds, or trust indentures, which are not executed in conformity with this part, but in which a conveyance for security purposes is made to a trustee or trustees for the benefit of one or more lenders. Such instruments are considered to be mortgages and are subject to all laws relating to mortgages on real property. Every such instrument, recorded as prescribed by law, from the time it is filed for record is constructive notice of its contents to subsequent purchasers and encumbrancers.