There are several serious caveats that make such a conversion not really viable:
- The bandwidth would be very narrow. It will almost limit you to a single frequency on 160m without making a physical adjustment to the antenna every time you want to move frequency.
- The performance would be very low efficiency just like you would expect from a short 25 foot tall antenna on 160m.
- You would be totally eliminating your 80m band capability for poor low efficiency performance on 160m.
You would be far better off to install a more efficient temporary inverted "L" antenna type for 160m than do this conversion.