If your question is asking if it has been too long since the crime to now convict someone the answer is: There is no statute of limitations on the crime of Murder and it can be charged and prosecuted at anytime.
For specific legal advice for your situation, consult an experienced criminal defense lawyer in your area.
California law provides a sentence of 15 years to life for second degree murder (Penal Code Section 190(a)). Various enhancements could add time to the 15-year minimum sentence.
If the person you are asking about was convicted in the 1970s, and would like to apply to modify his sentence, the judgment is most likely final and there is probably nothing that can be done. Petitions to recall and modify a sentence must be filed within a few months after sentencing. Notice of Appeal must be filed within 60 days after sentencing. Other than an appeal or a petition to modify a sentence, there are no other forms of relief generally available.
As Alec said, the basic term for second degree murder in California is 15 years to life. However, it's 20 years to life for a drive-by, and 25 years to life if the victim was a peace officer. That is before other enhancements are added.
