100 Octane with 12:5:1 340??

I would LOVE to do that but it is not available in Canada. If it does become available I will run it for sure. What kind of cost am I looking at to convert?

The cost isn't high to convert but you do need to burn more.

Your cruising range off one tank full will be significantly less. That's the big thing I don't like about E85. Someone needs to come up with a 30 gallon fuel tank for an a-body.