Thinking just a swap and reprogram of the ECMwhich a dealer can do or you can do online at GM Tech2Web or something like that as long as you have the proper cable. AESwave.com has the cable for $99 and 2 days access to GM's site is $55 last I checked. I'd personally take both vin numbers and call a dealer service dept or visit in person. Intake system and othe stuff comnes to mind but I'm 99% sure it can be done.I want to change my 2007AFM 3.9 (blown) for a 2007 3.5 . I have a (wrecked) donor 07 impala with a good running 3.5 . any advice ?? how difficult would this job be ?