for instance here are the specs on the two dodges i own, i have both are 1998's one is a cummins turbo diesel, one is an 8.0 litre v10 gas engine.
while the v10 makes more power then the diesel the diesels power comes on alot earlier.
ISB With Automatic Transmission
CUMMINS TURBO DIESEL)
Peak Torque: 420 lb-ft (
from 1600 to 2700 rpm)
Advertised Power: 215 hp @
2700 rpm
Governed Speed: 3200 rpm
No Load High Idle: 3500 RPM
and the specs for my v10.
Horsepower 310 hp @
4100 rpm
Torque 450 ft. lbs. (617 N.m) @
2800 rpm
so while the v10 makes more power, te diesel makes the power down low, therefore it tows better then the v10.