340 vs 440

i don`t know what i sould do. i have a 1974 dart sport with a 318 in it. i want more power!!! i am currently looking at 2 engines. there is the 340 that is completely rebuilt (stock rebuild) for $3900 or a 440 and tranny for $500. the 440 runs but could probably use a rebuild. i don`t have the skills or time to rebuild the 440 my self so i would have to pay someone to do it for me. what would you do????