Motor and transmission swap
 

Can I put 05 3.8 in an 07 Pacifica with 4.0

Motor and transmission swap. Will mounts line up what problems may I have if possible .

The 3.8L most likely has a 42TE four speed behind it
If you're not swapping a 4.0L and a 62TE six speed into it, you're in for a gigantic headache and vehicle that will never run and drive correctly, if at all.
Regardless of how much time and money you spend on parts....

Go to Car-Part.com--Used Auto Parts Market and look for an engine and transmission.
In my area a 4.0L engine and a 62TE can be had for under $500 each.
I paid $350 for my 4.0L and it runs great!