It'* about resistance.

Take my engine for example. It'* roughly 450hp and even more torque. The torque is what gets the car moving. Being that in 97 the Bonneville weighed about 3600lbs that'* a good amount of effort to move the car. Therefore all that power is required to flow through the trans and that'* a good amount of strain between 450hp and not moving.

Now take that same 450hp and transmission and move a car like a Fiero that weighs 2000lbs. Much easier to push and get moving. Therefore you can move this car at the same acceleration as the Bonneville from a stop and only have about 75% of the resistance than the Bonneville. That'* 25% that wouldnt' need to flow through the transmission.