How can you make a 67 Mustang handle big horsepower without a roll cage?

Or is a cage the only way to strengthen the unibody of a Mustang? I know subframe connectors are a joke on these cars. I am running 11.80's, but it is a street car. I would like to build a chis and drivetrain to handle (some day!) 700-800 horsepower. My body is already "rippled" from running the e.t. that I do. I'd like to make sure that car is rigid enough to prevent this in the future.