I'm restoring a 69 Lemans but ran into some serious rust/rot issues on the cowl, and under the dash as well. Has anyone removd the entire cowl/firewall before? Does it need to be cut loose from the a-pillars and how exactly does it come out? Do I need a frame machine to realign the new one as well? If I could replace the old one with one I have found in Cali, it would fix a lot of issues with the car.