Ford Powerstroke Diesel Forum banner

6.4 or 6.7

3K views 28 replies 7 participants last post by  fordpower643 
#1 ·
I am looking for a truck but I am not sure if I should get a 6.4 or save more money and get a 6.7. Any advice would help.
 
#2 ·
Either way you're gonna need to save money: to buy the 6.7 or for the potential for some crazy expensive repairs on the 6.4. I've had both, but I got rid of the 6.4 when I knew it was about to start having issues. Zero issues with my 6.7 so far. Even though the SD is set to be redesigned for '17, the current platform will be relevant for many years to come - especially since Ford is sticking with the 6.7 for the foreseeable future...
 
#7 ·
2015 and up is the 2nd generation of the 6.7L. It seems to have less issues than the earlier years. I have almost 20,000 on mine with zero problems.
 
#11 ·
It can... Think about what you are asking here though. This is EXACTLY why we are saying 6.7... Yes, the 6.4 in stock form with deletes can push more power than the 6.7. But not for long...

If you want big power from a 6.4 you are going to be tearing it down and doing a full build. Deleted 6.7s are actually starting to make somewhat close to a deleted 6.4 but without the massive failures. The 6.4 piston design is just garbage, they can and do crack under stock power. Once you add power and actually try using that power you will figure out how crappy the pistons actually are. Ask Keith... The 6.4 also retains the 4 bolts per cylinder, meaning with added power comes a stud job in your future. They don't blow as easily as a 6.0, but the cost is damn near twice as much....................

If you are going to do a full build go with a 6.4, if you just want a dd that you can get a decent amount of power out of... 6.7 it is. I love my truck, but they don't take kindly to abuse.
 
  • Like
Reactions: ZMANN
#13 ·
I would look for a 13 or 14 6.7. They have a nicer dash on the higher trim levels. I personally chose to avoid 11's and early 12's. A deleted 6.4 has the potential to make around 550ish hp with just a tuner and intake and exhaust the same mods on a first gen 6.7 will get you around 450ish. If you put a better turbo on it like a 15 stock turbo you can expect around 500ish and if you put the 15 fuel pump on it you start getting closer to 600ish then you start worrying about rods. The 15 and ups have a weaker transmission and the tuning options aren't as abundant as they are for the 11-14's but it's getting better.
 
#18 ·
6.4L can make massive power with just a tuner.

Agreed some of the internals suck, but I drove mine daily for a tad over 100k putting 550HP to the ground without a single engine related failure. Last I checked it was still on the road, with 120k, still pushing that same power untouched. 2010 Job 3.

To say you are going to have to spend big money on a rebuild is unwarranted, in my experience anyway.

I was more concerned with the transmission then the engine in my truck.
 
#19 ·
First thing is first... YES IT CAN MAKE MASSIVE POWER WITH JUST A TUNER! Why do you think SO MANY PEOPLE BLOW THEM UP! Ahhhhhhhhhhh sorry but this is exactly my point. He is asking what makes more power and is more reliable. You can't have both, it doesn't work that way. The 6.4 will make more power, but you will be tearing it apart much much sooner. It is NOT designed for 550+hp. And what did you do to blow the transmission? The 5r110w is a freaking tank... It is the one part of the 6.4 platform that you really don't need to worry about until you start adding air and fuel.

As for the 6.7, it will take much more abuse than the 6.4 will. The transmission is quite a bit weaker, but again with good tuning and a brain you don't need to worry about it.

I have 116k on my truck with no problems at all. I will not however be surprised if I crack a piston or drop a lifter. Why? Because I am putting 500+hp down right now... The extra fuel economy is worth it to me. My truck has also never seen nor will it ever see a boosted launch, race, or burnout. Well aside from in the snow... I don't expect to have any problems because I take care of my truck, but it won't shock me if it happens. And when it does I have plans...

I personally think the 6.4 is a better drive, but for the power he wants he will pay eventually. I honestly think he will have better luck with a 6.7 if he doesn't want to pull the motor any time soon.
 
#23 ·
I believe most of them get "blown up" because people can't keep their foot out of the go pedal. I would be more concerned at failures of an untuned truck with a 6.4L then one that is tuned. I don't want fuel in my crankcase.

Like you I tuned it for mileage, not because I needed to blow smoke and race my neighbors corvette. If you drive it like you stole it, you are going to have issues.

I pulled my boat on several long trips, if you were riding with me, you would have questioned the transmission as well.

However, I don't own a 6.4L now and probably never will again.

OP - Listen to the other guy. He has all the answers.

Better yet go read all the horror stories in the 6.4L section and also read about the ones who love theirs.

Having owned both, my vote is for the 6.7L if you can swing it. Leave it untouched. 6.4L for Ford was a short run motor, that is hard to work on, and in years to come won't get the support like a 6.7L will.
 
#24 ·
Ouch... Can't say I am surprised... But this is exactly what I am talking about lol. If you still owned that truck the only way to keep it from killing you financially is to fully build the motor right? And by then you would have spent more than you did on your 6.7 I am guessing (when you consider the trade). And for a DD that doesn't really make sense unless you are trying to a very long living or very high performance 6.4.

I love the 6.4, I think its amazing. But there is a reason I caution people before they buy one. If you plan to run anything other than stock power levels don't be surprised when crap like this happens. Granted, Keith you did do a fair amount of racing, boosted launches, and spent some time tied to another truck :look:
 
#26 ·
Yah I am looking around 15ish for when I decide to pull mine (or it decides for me...). It is also one of those things where I barely have more into the initial purchase of the truck lol. Really hard to justify spending that kind of money. I still want to stick to my goal of a 500+k mile 6.4 after the rebuild.
 
#27 ·
I am looking forward to seeing that crazy! Just to go off the last point, the 6.4 is actually my favorite truck out of all the superdutys. The looks, power, and comfort of the 6.4 is unbeatable IMO. But when they break, and they will with stupidity and a hot tune, its BIG $$$$ to repair.
Want a good DD that's pretty reliable with decent power? deleted 6.7 hands down.
Once one does a rebuild on a 6.4 though with delipped pistons and the works.. they can be very reliable and fun.
 
#28 ·
I bought this truck to be a hobby truck... I don't make my living off of it nor do I need it.

Crazy haz planz :p
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top