I would strongly recommend putting frame connectors in. I used to race the brown car in my signature on wrinkle wall slicks. I had a mild 351c with a C6, 4000 stall converter, and 4:56 gears. I didn't have frame connectors or a rollbar in the car. I ended up getting wrinkles in the roof right behind the doors. My current car is running a stroker windsor that should make at least 550hp with a 5 speed and 4:11 gears. I'm running frame connectors and a 8 point rollbar. Hopefully this will keep the car from flexing when I run it at the track on slicks.
Link to video of me racing my previous Mustang
