I guess I got lucky. I bought one from a seller on the big internet auction site and it has worked very well. I think I paid $110 or so including postage. I will mention one thing: please understand if your wiper motor is inside the cab (I can't recall where it was on the 59 but think it may have been inside), you will hear it working. I've asked friends who have bought more expensive conversion kits and they all tell me the same thing: No matter how much you pay for one, you'll hear it. It isn't loud or distracting...I'm not saying that but it is a "different" sound you have to get used to. Sort of like when you first got an icemaker in your refrigerator and you would hear the water valve refilling it and the ice cubes dumping into the bin. After a while you ignore those noises. I have decided that's the reason all wiper motors were moved to the other side of the firewall...so you didn't hear them. The best news is you'll enjoy using your wipers a lot more.
Oh, one more suggestion. If you can, remove your wiper transmission assembly and clean and lubricate the rotating ends (where the wipers connect). Make sure they're not worn too much, also. If you get these working nicely and smoothly it will make a noticeable difference and I don't know about others but mine needed attention. Mine had gotten to the point where they squeaked and sort of "jittered" when they were in use and that translated into poor blade action (and maybe a little noise also). Good luck!
