hello Im new here ,live in southern AR . my wife owns a 01 300m that got hot it still starts and run but only for a few minutes then revs up and down and dies it has a hard rattle almost a knock in it when it is reved up believe it needs a new engine . i found a 3.5 out of a 07 300 with around 5000 miles on it was wondering if it would swap out

 

Welcome to the forum. You might get a more knowledgeable response by posting your question in the 300M forum further down the front page, but it's my understanding that Chrysler re-designed their engine management system (computers and sensors) around 2004 and your engine swap is probably going to be more complicated than you had hoped it to be. Replacing the engine on a 16-year-old car may not make economic sense if you can replace the car for less money/hassle.