It depends on what shape your original proportioning valve is currently in. I had one on my 65 that started leaking, so I went ahead and bought one of those kits you posted a link to, but the PV still leaked after I installed it. Those things aren't free, either. I ended up buying an adjustable PV, and haven't had any problems since. I wanted to keep the original PV, since it was an original, but guess it wasn't in the cards for me.