I think this is fascinating! I had always wondered about this song. My high school (in New England) was a combination of two neighboring towns and we found that even just between our two towns there was a difference (albeit slight)!

I learned it this way:
Crocadilly, oh my, croc croc croc
Say cinqo cinqo, cinqo cinqo sock-a-locka
Follow, follow, stick your head in jello,
Make it turn yellow,
1 2 3 4 5 6 7 8 9 10

The kids in the next town said "stick your head in yellow jello".