26 C.F.R. § 1.9003-3
Under section 302(c)(2) of the Act, the period within which the assessment of any deficiency or the credit or refund of any overpayment attributable to the election may be made shall not expire sooner than 1 year after November 15, 1960. Thus, if assessment of a deficiency or credit or refund of an overpayment, whichever is applicable, is not prevented on September 14, 1960, the time for making assessment or credit or refund shall not expire for at least 1 year after November 15, 1960, notwithstanding any other provision of law to the contrary. Even though assessment of a deficiency is prevented on September 14, 1960, if commencement of a suit for recovery of a refund under section 7405 of the Code may be made on such date, then any deficiency resulting from the election may be assessed at any time within 1 year after November 15, 1960. If the taxpayer makes the election he shall be deemed to have consented to the application of the provisions of section 302(c)(2) of the Act extending the time for assessing a deficiency attributable to the election. Section 302(c)(2) of the Act does not shorten the period of limitations otherwise applicable. An agreement may be entered into under section 6501(c)(4) of the Code and corresponding provisions of prior law to extend the period for assessment.
26 C.F.R. §1.9003-3