I submitted a few 8606s for a few years of forgotten non-deductible IRAs. It has no impact on 1040 because I paid the taxes on the non-deductible IRAs. It is needed to track the basis for conversion to ROTH to avoid paying taxes twice.
I sent just the 8606 forms. a year later I was told by IRS to send 1040-x. I can't figure why but I am sending the 1040-x with explanation in Part III Explanation of changes because there is no line that changes on the 1040x. I will keep you posted if it works.
