what could be done to increase fuel millage on this model, and with the 4.3 gear ratio does this make it more like a 3/4 ton or just under?

if you want better fuel mileage switch to 3.73 rear gears. and im not positive but i dont think dodge even offers a 4.30 i thought they only had a 4.10 but any way, it doesnt really increase your towing capacity, basically your leaf springs and axle its self govern that, all a 4.3 rearend is going to do is give you gobs of torque

yeah, i havnt ever swapped out my gears, but i have the 3.73s, and my truck has great mileage, great towing power, could be better, but id need a bigger engine for that, also some other stupid little things to help, keep your air filter clean, make sure your tires are inflated to the right psi. also you might look into a few performance items, like my truck, it has a jet pcm chip, it helped my truck out alot. but if your not getting that great of mileage out of an08, then maybe you need to buy something different? i know alot of things change between the years, like my 96 1500 gets better mileage than my moms 06 expedition

k&n filter would help a bit, and you can get better towing with that gear but it's also rated by how much the sespension can take too