I also replaced the original stuffing box with the PSS shaftseal. It's easy to install and works well with no drips in the bilge. To install, you should probably have the boat hauled and then:
1. Loosen the nuts on the flange, and slide the shaft backwards several inches. Sometimes this means inserting an appropriate sized socket between the flanges and using the flange bolts to force the shaft out.
2. Remove the old stuffing box, and clean up the tube and the shaft.
3. Install the new seal following their instructions that come with the new seal.
4. Relaunch the boat, and burp the tube by initially allowing a small amount of water to enter the tube for lubrication and cooling purposes.
I'm delighted with the installation and performance of the one (1 1/8 dia )shaft on mine.
Don Wagner C&C 41 CB Der Baron