According to Jane's encyclopedia of world aircraft here are the comparisons:
Boeing 707-320C
powerplant:4*JT3D-7
max speed:627 mph
service ceiling: 39,000 ft
range: 5,755 miles
MTOW: 151318 kg
wing sweepback= 35 degrees
Douglas DC-8-63
powerplant: 4*JT3D-7
max speed: 600 mph
range: 4,500 miles
MTOW: 158,757 kg