Excess Petroleum Profits Tax Act of 1979 - Amends the Internal Revenue Code to impose an excess profits tax on petroleum corporations equal to 90 percent of the amount by which the taxable income of such corporations exceeds the surcharge exemption for the taxable year. Defines the "surcharge exemption" as the percentage rate of return on the capital investment of a petroleum corporation equal to the average rate of return on capital investment for all manufacturing corporations for the taxable year. Exempts from the tax: (1) petroleum corporations which have an invested capital structure of less than $2,500,000; and (2) corporate income which is set aside in a fund for purposes of investment in petroleum research and development. Permits a deduction from corporate income, for purposes of computing the tax imposed by this Act, for investments in: (1) exploration or development of new domestic fuel; (2) increased domestic productive capacity; and (3) research and development of new domestic energy sources and of energy technology. Allows an investment tax credit for investment in facilities for research and development of new domestic energy sources and for facilities to increase the domestic energy supply.