A-518 in a J-body?

Has anyone done it? I've been researching it a bit, and can't find J-body info. Will there need to be floor pan/crossmember cutting/fabrication? I'm thinking of just making a cool cruiser out of my Mirada. Magnum engine, overdrive, a little steeper gear and make all the accessories work. Still in the planning stages. Will be for a little while.
Feel free to chime in!
By the way, I found the PTC website and will be doing their conversion for overdrive and the convertor lockup....

A-518 in a J-body?
Author: OhioMopar