Mileage with a Motor Home

[JRE CPA]

In a message dated 98-03-30 09:05:37 EST, you write:

<< Will it not take more than headers to pull the max torque down by
 nearly 30%?? Even a 454 may tend to lug at 1800RPM on a machine the size
 of your MH. If it lugs, the vacuum drops, and with it fuel economy. The
 reason MAX torque RPM gives best fuel economy is because it allows
 highest sustained cruise vacuum. Anything above or below tends to drop
 off vacuum if running anywhere close to rated load. >>

Your theory may be correct for full throttle torque, but I don't know too
many people that drive at full throttle. You need to know the part throttle
torque curve of the engine to know what rpm you can cruise at without
booging down the engine. The flatter the torque curve of the engine is
the lower you can run the engine at cruise speed.
My two cents worth.

James