I was seaching on google and got a post whcih goes like this:
Do not specify TIME=1440 on your job - even if your site doesn't automatically flush your job (many do). TIME=1440 is not a proper choice for programmers to make.
If you are trying to prevent a time-out abend, see your systems support or operations people. Your site probably has different job classes for different resources required. There may be a class already defined that will accomodate your cpu time requirement. If not, they can tell you what you need to do.
It would be good to determine just why the amount cpu time is needed. If your job processes many millions of records, it may very well not run in the same class that supports compiles and small testing.
Why 1440 is not allowed?