From
http://www.delta.com/travel/trav_serv/bag_info/carry_on/index.jsp#limits
Baggage Weight and Size Limitations
All checked baggage is subject to the following restrictions:
Weight
Items on domestic flights should not weigh more than 50 lbs.
Items on domestic flights weighing between 51 and 100 lbs will be charged an excess baggage fee.
Items on international flights should not weigh more than 70 lbs.
Items on international flights weighing between 70 and 100 lbs will be charged an excess baggage fee.
Items over 100 lbs will not be accepted
Size
Items over size limits will be charged an excess baggage fee.
Items cannot exceed 62" (length + height + width) limits.
Items over 80" will not be accepted.
All carry-on items must fit easily in a Size Wise unit (approximate dimensions 22" x 14" x 9") and must weigh less than 40 lbs.
Some packages, sporting goods, dangerous, fragile or bulky items may require special handling. Please follow the link at the left for additional information on special items.