I'm interested in updating my existing 1908 wood windows, rather than
replacing them. I'd like to get rid of the weight-and-pulley balances
so that I can insulate the weight pockets. Of the alternatives, I
like the block-and-tackle system housed in a jamb liner, like new
windows or sash-replacement kits (e.g. Marvin Tilt-Pac) use. Is it
possible to buy these block-and-tackle jamb liners separately?