set ulimit file(blocks) to unlimited

Hello:
Command $ plimit $$ shows:
...
   resource              current         maximum
  time(seconds)         unlimited       unlimited
  file(blocks)          8000            8000
  data(kbytes)          unlimited       unlimited
...

I would like to set the file(blocks) to unlimited. Issue command
$ ulimit -f unlimited
ksh: ulimit: exceeds allowable limit

(1) How could I make the change and keep it permanent ?
(2) Where is Solaris 10 keeps the maximum value for file(blocks) ?

Environment: Solaris 10.

Thanks.
Warren