Brian has made some excellent points. I would look carefully at the frame from the horns (front) to the cross member, look for heated and repaired areas, kinks, rivet replacement, anything that looks out of whack. And like Brian says, 1/4 inch is often what the factory deemed acceptable fo out of square. Moving this to basics, I believe it will get more exposure there, some very helpful info.
"When I was younger, I could remember anything, whether it had happened or not." - Mark Twain