Not saying the careful use of a torch will nessasarily cause damage...but a torch and a welder in the wrong hands will cause undo stress to the point of sag or frame crackage in the future...I personally have notched my 65 and have caused no damage but i also used a kit that had backing plates and BOLTED on after the cut...no welding required. Anybody contemplating a homade c-notch using a peice of pipe welded to the frame is asking for trouble down the road...Most metal on a 40+ year old frame has rust and weak spots already.
