If the redevelopment plan contains the provision authorized by Section 33670, the agency and the legislative body of the community may, either before or after the authorization of general obligation bonds for the purposes permitted by Section 33630, enter into an agreement that the principal amount of any such general obligation bonds sold for such purposes, together with all interest which the community may pay thereon, shall constitute a loan by the community to the agency for the purpose of refinancing the redevelopment project, and that, subject to any prior pledge of or claim upon the moneys in the special fund provided for in said section 33670, the moneys accruing to
such special fund are irrevocably pledged to the repayment of such loan until there has been repaid to the community from time to time from such special fund the principal amount of such general obligation bonds plus all interest which the community may pay thereon, less such part, if any, of the proceeds of such general obligation bonds which were not used for such purposes, and less any premiums and accrued interest received by the community upon the sale of such general obligation bonds.