Would a transmission from a 2003 durango fit right into my 2002 dakota?

Hi, I just bought a 2005 5.7L Hemi as a rebuild project. Plan for now is to put it in my 2008 Wrangler to replace the one I swapped in it about a year ago. The engine has 250K miles and was run hot with a bad water pump, both heads have dropped seats and the heads are toast. Lower end looks...

Im trying to upgrade my exhaust but iam not sure what size the pipe diameter is

Just picked up a used 2003 Dak 4x4, quad cab with the 4.7L engine. This thing is a pig on gas. Have read some older threads and seen some people list generic mods ("exhaust, tune, etc.") but am curious as to what specifically I could do to get some better gas mileage. What sort of exhaust mod...

Has anyone here has/doing an engine swap on their 3rd gen dakota? (3.7 to 5.7hemi) just curious what problems you guys have ran across things to look out for etc.