Probably just as fast (and just as cheap) to replace the switches with new ones w/keys. Think mfgsupply.com has switches that will work. Here's switch numbers I found on their website for manual start switches:
Part# 01-139 69 - 78 TNT
Part# 01-160 79 - 81 Blizzard 5500
Even though they claim to fit, I would still compare yours very carefully to the website photos to make sure the terminals look like they match before you order anything. Electrical parts can be tough to return.
If you just want to see if the sleds run, just unplug the ignition switch and use the kill switch to control the engine spark.