My '74 started missing. Should I get a tune up
now before winter, or wait until spring? I get
it out a couple of times a month in the winter.
It's a 350 automatic.

I would do it now Don. This way when you do take it out or just run it a few times during the winter, it's not such a PITA. Cold weather and out of tune engines don't mix well. And it's one less thing to do this spring.
Sarge

Yah, Do it now one less thing off the fix it list,I dont know how your list is but mine never seems to get any shorter,you do one thing on the list and add two more things to it.Come spring you'll have another page to deal with,it never ends.a tune up wont take that long,and while your bent over the fenders looking down into the engine compartment you'll find half a dozen things to add to the list! Ron 78