Temporary National Economic Committee Act - Establishes a Temporary National Economic Committee to be composed of ten members selected from Federal agencies, the House of Representatives, and the Senate. Requires the Committee to make a full study of the American economy including: (1) the structure of the economy; (2) the concentration of economic power and financial control over the means of production; (3) the structure of Federal, State, and local government finances and the impact of governmental fiscal, monetary, tax, and regulatory policies upon the structure of the national economy; and (4) the effect of specified economic factors upon other economic problems. Directs each department, agency and instrumentality of the executive branch of the government to furnish such data, reports, and other information as the Committee deems necessary to carry out its function. Authorizes the head of any department, agency, or instrumentality of the executive branch of the Government to furnish such personnel and services as the Committee may request to assist it in carrying out its functions. Requires the Committee to transmit to the Congress and the President a final report of its finding not later than September 30, 1977. Terminates the Committee sixty days after it transmits its final report. Authorizes to be appropriated such sums as may be necessary to carry out the purpose of this Act.