Contemplating a Swap

Been searching the forums, figured I'd ask and get an updated opinion.

I have a 68 Barracuda, with a 318 in need of a rebuild/new motor. I went to talk to my mechanic about building a 390 stroker and he offered me a 2007 5.7 HEMI from a charger for 1500 bucks everything included (minus trans), as I've read my 904 will bolt right on with minor modification.

I told the mechanic I'd get back to him tomorrow morning. Question being, considering I want more power than the 318 should I pull the trigger?

I can work out labor with my mechanic; but, what am I looking at as far as parts costs? I'd like to be under $3500, including the motor... can it be done?

Thanks in advance!