Extending and existing zpool - Solaris 10

This is on the control domain with physical internal disks.

Current config is a 64Gb mirrored root pool.

Problem is both 300Gb disks were sliced with 64Gb as Slice 0 - and its this that is used in the zpool.

One of these disks is faulty and have just replaced. This time I did not slice the disk and allocated s2 (entire disk) to the current mirrored zpool. Of course, its still 64Gb because the first disk in the pool is only 64Gb.

If I take that original disk out of the mirrored pool, repartition it then re-add as s2 (300Gb complete disk) will I then have a 300Gb zpool or will it remain at 64Gb?