What about zinc?

A56, that's a great point, and it's well taken but there's one problem with it. I just can't leave my car alone all winter long here in Minnesota. I've nicely finished out my garage - sheetrocked and painted walls, painted floors, gas furnace in the ceiling, six foot deep mechanic's pit in the floor. Once my Duster is waxed up and clean, it looks so good sitting there that I just have to start it up and run it. I've set up the slant six totally stock, so when it's cold and I start it up it runs on the high idle setting before I kick it down. The air bypass door in the air cleaner intake opens up to provide warmed air to the carb off the exhaust manifold. The engine starts transferring coolant to the reserve tank, the temp gauge comes up to the full operating temp and stays there. For some inexplicable reason, I just love watching this process unfold even though I can't back it out of the garage because there's two feet of snow out there. The best part is listening to that lovely solid lifter motor run at high idle, then kick down to a butter smooth idle. So yes, I can see your point, but I just can't resist the temptation to warm it up every few days. You look forward to small things like this when you live in a frozen tundra all winter long. Anyhow, there's my lame explanation. Show's how sick I am.
I'm not to far south of you and I start mine up a couple times each winter (usually during a January thaw) and drive it around the lot to lube up the transmission and rear end. I don't get it out on the street with all the salt. I usually wait for a couple spring rains before getting it out on the streets in the spring.