I think this is where you're going and it's worth a try:
Drive the car in a situation where it makes quite a bit of power so the headers get nice and hot.
Put a jack under the collector and jack it up.
I bet it works, just don't get too frantic with the jack or you'll oval the collector.
No use to use a rosebud when you have a 300+ horsepower torch at your right foot!

R.