Fed-Ex is cheaper to ship large items with than UPS or USPS. I had my 21" computer monitor go bad under warranty. I had to pay for shipping to send it back to the manufacturer. It weighted 90 lbs - USPS won't go over 70lbs, UPS wanted $50 and Fed-Ex shipped it for $36. Check Fed-Ex's website here:
Fed-Ex
It will show you what it will cost. You can even schedule them to come to your door to pick it up. Also, I checked and put the dimensions for a '72 bumper in their rate calculator and it showed they would take it.
Roberty