I've always figured I'd use a good 'ol trusty 300 in my future 4x4 plans, given the decent off-idle/low end grunt and quasi-decent fuel mileage capabilities, but I got to thinking about other options, and figured I'd ask you guys what your thoughts were.

Looking for something with:

15+mpg capabilities
Fuel Injected
Lots of Low-end Torque (or the ability to build low end into it)
# of cylinders is optional
Forced induction is optional
Must be Daily Driver Friendly (idle quality, etc)
Ease of swap into a Ford truck would be helpful
The ability to mate to a 6 speed trans
Must be very reliable

I would like to keep it in the FORD family, but I'm open to all suggestions.

This motor would most likely be going into either a '67-79 SWB F-100/150, '78-79/'92-96 Bronco, '92-96 SWB F-150, or possibly a modified Bronco II.

So basically, this motor will be pushing a 5000lb + brick through the air with 35" tires, lugging up and down hills, through mud, etc...and still cruise the highway doing 70+. I realize the "15+mpg" with these qualities might be a little far fetched, but the best mileage I can get would be beneficial.


So what are your opinions, folks?

 

for what you want, i would stick to the 300 6 cylinder.

with a V8 you are not going to see decent fuel mileage with high RPM torque.

 

Your expectations are a bit high. My 96 4wd single cab shortbed 300 on 32's struggled to get 14-15. Id personally go for a 351 with a little work done to it, in same application it'll be the same fuel mileage as the 300.

If mileage wasn't a concern it would be 460 hands down.

 

I was thinking about a built 351w, but wanted something more modern. Which got me to thinking about the late model 5.4, 6.2, and 5.0....none of which are known for producing anything significant in the off-idle/low range....at least not without a blower. Also thought about the 3.5l Ecoboost V6, but that's pricey and I'm not sure how it would fare off-roading.

I agree, if mileage weren't a factor, a 460 (or stroked and poked 351w) would be plenty. But the idea of efficiency and best mileage possible strike that option down.

 

To many electronics on those for me

 

Larry, a 300 with 410 gears and 33 inch tires should be able to hold 14-15 mpg.

 

If you really plan on thrashing the engine and want some RPM say away from the 300. Its a great tough engine down low, but it does NOT like high rpm.

Now since you like newer engines that opens up a whole new world of possibilities for fuel economy and highway performance.

My old man has a 5.4l bone stock in his 09 F150. It has way more than enough power for that truck and the 4low gearing is a stump puller. I also had a 4.6 2 valve engine in an f150 and it was low on bottom end torque. These engines varied quite a bit in year and type.

My recommendation would be a 3 or 4 valve 5.4 engine/tranny/transfer case. They will have plenty of power for on and off road and have OD. If budget lets you then by all means put a turbo on it and have even more fun!

 

I had a 5.4 in an '08 F-250. Nice Mustang engine, terrible truck engine. So for an off-road engine you need to ask if you want a Mustang engine or a truck engine. My 5.4 had no power below 3000 rpm, but for mud, sand or hillclimbing it's power in the high end would have been great (with good mileage when you don't thrash it too). For rock crawling I'd want something with more low end, but you can make up for that with crawler gears too.

As 61steven said, the 300 is at the opposite end, good down low where you want it for rock crawling, but won't hold up as well if you want it to scream through a mud pit or up a hill.

Something like a 351 will be anywhere along that continuum, depending on how it's built. It can be as good or better as any 300 at the low end, and can pull the high end way better than a 300. It'll have more low end than a 5.4 (unless it's really built for the high end), and could be as good up high. But a 351 will probably be behind either of the others in mileage.

You need to make your own trade-offs. But if it was me I'd say a stock to mildly built 351 would hit the sweet spot pretty well. Good low end, good high end, good mileage. Not necessarily great in any of those categories (compared to the competition), but also pretty easy to fit into most applications (not as long as a 300 or as wide and high as a 5.4), not ridiculously heavy, and relatively simple to work on (really important for me in an off-road engine)

 

I'm gonna get crap for this one.......

If money isn't a huge deal and you are looking for a good investment that can do everything you're asking for with ease....... Go with a 12Valve Cummins ...... It's heavy.... It can make great power.... Easy to get to running with minimal wiring.... Should easily get the mpgs you're wanting. Its the only engine that I can think of that won't have a problem moving 5k pound effortlessly has plenty of low end grunt and gets good fuel mileage....

One thing I would ask myself if I were you and were considering this alternative is... Is the rest of the drivetrain up to the abuse this engine will throw at it?

My .02 cents.... Let the crap fly.....

 

OK, I'll sling first. Just kidding, I think a Cummins would be a great truck engine, just not my choice for a best off-road engine.

My first thought against a diesel in an off-roader is that diesel exhaust stinks. No biggie when you're driving 55 mph and it's all behind you, but not so pleasant when you're crawling with open windows. Or are crawling behind a diesel with the top down on your CJ5 (I followed a diesel on a trail once, I don't want to do that to anyone else). The smell alone DQs a diesel in my book.

Second is the weight. The more weight you are carrying the more everything else needs to deal with. In an expedition vehicle that's going to haul everything including the kitchen sink? Great! But in a rock crawler / mud runner / hill climber / dune runner I'll take a small block.

And for the higher speed venues I'm not sure a torquey diesel is the best bet. The power curve would be GREAT for rock crawling, but I think a gas V8 power curve would generally work better in mud, sand or hills

 

A gasser with no cats and a substandard tune doesn't smell any better than a stinky diesel

Sent from my Telegraph using IB AutoGroup

 

for a rock crawler a diesel has the off idle grunt you need.
but for a mud/beach runner, a diesel flat out sucks.
unless you keep the rubber band wound real tight, the only thing the weight of that diesel is going to do for you is get the truck stuck.

i been there and done it way too many times.

 

Maybe so, but just because you can make a gas engine stink doesn't mean it has to. Now if you can tell us how to make a Cummins not stink you've got something.

 

Toss a doc on them...

Keep them maintained and put good fuel in them and the smell isn't as noxious as a stinky gasser.

Sent from my Telegraph using IB AutoGroup

 

I personally don't think a diesel stinks....