I have been through three aftermarket heater valves in my 83 in the last
two years. None of them worked well in any way. If they were loose enough
to move without folding the cable in half, they leaked and ran hot air in
the cabin all summer.

Cheap enough at about ten bucks each, but they don't work. GoWesty has an
alternative for about eight times that price, but it has a lifetime
guarantee, and hey--guess what--it works as advertised. If you want a valve
that turns all the way open to heat the cabin, and all the way closed to
cool it, without bending your heater cable into pieces, I think the GoWesty
product is your only alternative today. And then there's that lifetime
guarantee.

Jim