thanks for your perspective. I really don't need any more power. I just want to improve mileage. Propane is about $2.00 per gal. I am told that Fireumup has converted a f250 that was getting 15 miles per gal and now they are getting 26 miles per gal. I get 9.5 miles per gal while pulling, 11.5 just going around town and not pulling. I'm alittle afraid of propane because it will cause the engine to run hotter. I would need to increase the exhaust to a 4" rather than the 3" stock. I just put a Banks billet torque converter with the trans command module to increase transmission efficiency. We'll see if we get better mileage since the tranny won't be slipping up those 6% 10 mile long grades. I'm afraid there not much I can do to lower our wind profile. My RV is a tall one at 13.5'. I'm heading out to CA for the winter and then heading up to Alaska for the summer. I would like to get alittle better mileage especially since diesel is even higher in Canada. Go figure they export more of their oil than they use and they are still more expensive than in the US.