I would like to add some low gearing to the road bike.... With it's 53/43 crank, and the fact it's Raleigh threaded...

Wondering if one of those big capacity freewheels might work... I saw a 6 speed 14-34 tooth one available from a local shop for under $20, but would it work. My junk box has a high capacity derailleur in it, so I am not concerned there.....