"DD" == Drew Dalgleish writes:

DD Hey he's retired . What's the rush to get there? The RV 12
DD will get way better miles per gallon

Not necessarily. It's been demonstrated often that RVs with different
size engines get similar mpg when operated at the same power (hp)
settings. What the bigger engine gets you is a much better reserve for
climb and cruise, if you want to use it.
--
Why can't the ant and the caterpillar just get along? One eats
grass, the other eats Caterpillars... Oh, I see now.
- Jack Handey