Hey all, I’m picking up a 79 with the ignition key tumbler section of the switch missing.
whats my options for replacement?

 

By "tumbler" you mean the mechanical barrel assy the key inserts into? Or the wiring component module that fits on the back of this?
If you need the mechanical you have 2 choices
-pull one off a wreck (or buy one off someone's wreck via the Parts for sale Forum here)
-buy a new one, which I see regularly on ebay, suggesting that Mazda may still offer these. Figure $150+
You will need to use a 1979 or 80 part
With new you would presumably get a key as well. Used...? maybe? Tho I would guess a locksmith could fashion a key if you supply the tumbler assy. But check the cost of that a factor that in to used vs new.

Used one requires drilling out the break-way bolts that fasten it to the column at the factory. You will want to be sure your seller does not muck up the lock assy doing this or you will have a devil-of-a-time reattaching to your column!

Stu A
80GS
AZ