Fuel economy (odd ball)
What is the difference in mpg in a slant 6 4 speed pickup compared to a 4 speed volare or an automatic dart?
That's an apples and oranges comparison, because wind resistance is your biggest highway contributor to fuel consumption. Choosing a truck instead of a sedan doesn't seem likely to help you.
I am driving my 74 sedan about 80 miles a day back and forth to work and was wondering what I might save going to a 4 speed with overdrive
Need a bit more information. An overdrive gear will almost certainly save money, as long as the engine still makes enough torque at whatever is the reduced rpm. But it's going to change how you drive in the city. Sometimes an overzealous choice of "highway gearing" actually hurts city mileage because the engine ends up working too hard at those lower rpms.
Right now my car is getting about 7 kilometers a litre but the valves need adjusting (hopefully saturday) the rear most likely is getting worn out, and the engine doesn't run perfectly smooth
Um, it seems like you've got a whole lot of things you could do that are a whole lot easier than changing a transmission! Valve adjustment, timing check, making sure the vacuum advance canister is still working...
Let's see, 7km/l = 16.5mpg. This is in an automatic 74 Dart in a snowy winter climate? Might not be all that far off. Depending on the rear end ratio, I wouldn't expect more than about 19-20 mpg (8km/l) anyway, for those weather conditions.
Here's how difficult it is to predict gas mileage based on how smoothly you think the engine is or isn't running: I once tuned up a 170 slant six in a little 1965 Valiant to the best of my then-inexperienced ability, got my highway mpg all the way from 14 to 16. Frustrated. Everything seemed to be running just fine, it purred like a kitten, but drank fuel. Rebuilt the carb. Still purred like a kitten, highway mpg jumped to 27. Learned a lot, that day.
- Erik
64 Valiant, 170 3-spd
82 Volvo wagon, 5.0 5-spd :)
