I found the 767/707 comparison data on the Boeing website, and the numbers between the two planes are very similar. I have always heard that the 767 was much larger and heavier than the 707. Note, WTC 1 & 2 were meant to be able to withstand a 707 strike travelling at 600 mph. Here are some quotes by the WTC structural engineers:
707-320B
Wingspan 145 feet 9 inches (44.42 m)
Length 152 feet 11 inches (46.6 m)
Wing Area 3,010 square feet (280 m2)
Gross Weight 336,000 pounds (152,400 kg)
Cruising Speed 607 mph (977 km/h)
Range 6,160 miles (9,913 km)
Service Ceiling 36,000 feet (10,973 m)
Power Four Pratt & Whitney JT3D turbofans of 18,000 pounds thrust each
Passenger Cabin 141 passengers mixed class or a maximum of 189 all economy
Boeing 767-200ER
Cargo 2,875 cu ft (81.4 cu m)
Engines
maximum thrust Pratt & Whitney PW4062
63,300 lb (281.6 kN)
GE CF6-80C2B7F
62,100 lb (276.2 kN)
Maximum Fuel Capacity 23,980 U.S. gal (90,770 l)
Maximum Takeoff Weight 395,000 lb (179,170 kg)
Maximum Range 6,600 nautical miles (12,223 km)
