I know there are alot of threads out there about swapping motors. I have been looking at the 4.7, 5.2 and the 5.9 to swap my 3.9 6 cylinder. The motor still runs decent, but it is seriously lacking in the power department once you load up your family, fill the bed full of stuff and add a trailer. So my questions are this: Which of the V-8 engines are the most reliable, have the most hp/tourqe output and the best fuel mileage from the factory? I know my motor mounts, and tranny will bolt up without a problem, as well as most of my accessories. What motor should I be looking for? Any help would be greatly appreciated

 

6.7L Cummins Turbo Diesel
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if you have the 3.9L, the 5.2 and 5.9 will hook up to your trannt. if you got a 3.7 the 4.7 and 5.7L Hemi will hook up to your transmission... So looks like a 360 is in order.

 

I have a 318 (5.2), don't bother with it. Its not a bad motor but it isn't that fast and it gets terrible MPG's (I know that's not the point but it really sucks, so to speak). I'd go for the 360 (5.9). To answer your questions
1) the 5.2 is a a good engine, I have 116K on mine and I haven't had any problems other then it doesn't like damp weather. It runs rough when it rains and recently it wouldn't start after a rain. that however could be my fault as it needs new spark plugs and a distributer cap.
2) It makes 230 hp and 300 lb-ft of torque, its good but personally I wish I had a bit more.
3) MPG expect 12ish city 18 highway. Maybe a bit better in the city if driven nicely, but you wont do much better on the highway without a 5 speed manual.
Good luck, I dont mean the bash the 5.2, most of the time its a very good engine.

 

The 4.7 is by far the most reliable but with that being said, isn't as pratical for a swap as the 5.9. The 5.9 will mount right up and give you the best torque by far. So that's what I'd go with. Plus the aftermarket is lightyears ahead of the 4.7. Mainly because that thing is old as dirt.

 

Put in a Hemi you wont regret this swap I did and I'am working out the bugs and booboos in this swap.

 

So for curiosity's sake, briefly, can somebody please tell me what changes would be necessary for swapping a 5.7L with my 3.7L? How about the 4.7L?

I would really enjoy more power (especially with my quad cab), but I don't want a burn out machine that would be impractical to drive on a regular basis.

None of the v8 swap threads specifically address this for me.