I've got an older one ton Ford

 motorhome,  I  leave my driveway at about 10 or 11,000 lb.  Needless to say I chew through brakes especially front. Exhaust brake would be great but cant find any.

 

Whats the reason there's no exhaust brake for gasoline Motors?

Edited November 12, 20195 yr by 015point9
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I did a little bit of reading and it looks like it's mostly because the motor is already sort of braking when the throttle plate closes.

Exactly, diesels have exhaust brakes because the unlimited airflow combined with high compression means there isn't any restriction in the motor. 

 

Gas engines don't have that problem. The issue with some gas motors is that they are always fueling, even above idle and 0% throttle which will overcome some of the throttle plate drag.