I'm thinking about an engine swap for my '97 F-250HD crew cab and I'm looking for some (at least semi-informed) opinions. It currently has a 460 with an E4OD and 4.10 gears. I'm plenty satisfied with the power, but definitely not with the mileage. At this point this is more a pipe dream than making actual plans, and I'm a couple of years away from anything actually happening. But I'm considering my options and was wondering what others thought.

I don't want a diesel, and I could give up a little of the power I've got with my 460. But I want significantly better mileage. I'm hoping / dreaming that I can get close to 20 mpg on a 60 mph highway trip.

I had a 5.4L in an '08 F-250 CCSB. That got around 18 mpg on the highway, so it's in the range. But I hated driving it with the high rpm needed to get any power. So the mod motors are out of my consideration.

A friend had about a 2017 F-150 with the Coyote 5.0L. He got near 25 mpg on the highway if he wasn't playing with it, so that is definitely in the running. And from what I've gathered it makes enough power lower in the revs that I wouldn't hate it. But I want a 5 spd manual trans. Are there any choices for 4WD truck manual 5 speeds for a Coyote? And what is the support for an install like that? I'm sure the ECM wouldn't be happy without the automatic trans that the F-150 would come with and I don't want to have to run a 2017 instrument panel. Are there resources for thinning out the wiring harness and getting an ECM to run it in an older truck with a manual trans? And how expensive would that swap be?

That brings up a Ch*vy LS, probably a 5.3L or possibly a 6.0L. LS motors are plentiful and cheap (compared to a Coyote), and they have plenty of aftermarket support for sticking in an older vehicle with a manual trans. A couple friends have them and they've been happy with the power curve (better low end than the Ford mod motors). I'm not sure about the gas mileage with these, I've heard pretty good, but I've also heard more mid-teens. I know it's not a Ford, but I'm OK with crossing brands if there's enough reason to.

I've also thought a little about trying to build a 351W to be more efficient. Better heads and things like that which improve power are actually improving the efficiency, so if you don't use the power you get you can actually use less gas. I probably wouldn't do better than about 15 mpg like this though, and that doesn't really meet my goals (although it might not be worse mileage than an LS, and has the advantage of being Ford).

Any thoughts on any of these? Or are there any other options I should be considering?

 

The LS wins hands down, so doit...

Now that that bit of blasphemy is out of the way, the coyote (is a mod motor, isn't it?) would be great & you could do it reasonable if you shopped I believe.

I figure you would be the perfect person to do a 5.8/aluminum heads/stroker kit & Stinger. Hell, drop a turbo on it.

Good luck, watching with interest.

 

A built windsor certainly can be efficient and get good MPG. We've got a customer with a windsor based turbo engine in a fox body Mustang that makes north of 700hp and he got over 30mpg on a recent trip to a car show in another state. I know that's a Mustang which is a whole different beast than a truck in terms of weight/aero but that's also significantly higher than the stock MPG for that vehicle even though it now makes almost 4x the power.

 

I'm thinking the only reason the 5.0 got such great mileage is from variable cam timing and all the computer controls. Nothing a 460 has. I think if you put a 5.0 in your heavy truck it would likely not get that great of mileage. Better, but not double.

My '95 F150, 302/3.31 gears/auto got 18+ on the highway if you stayed at 65 mph and out of the big hills. My current '95 has 3.08 gears and doesn't go as well on mileage because it downshifts(unlock converter) on the highway all the time on long grades. It lugs too much. I thought it would be better, but lesson learned....that 302 needs a bit of RPM to carry the truck at highway speeds.

I had a brand new '96 F350 SC/DRW 460/auto/4.10. I put a Vortech supercharger on it. "IF" you didn't plan on pulling heavy loads, putting some faster gears in your truck and adding some boost (mine had 5#)would likely help it get 15+ mpg. Hey, that's a 50% increase. Mine only got 10 mpg no matter what I did, but I was into the throttle all the time back then. Gas was under a $1/gal! I did use it to pull my 40ft Haulmark race trailer.(14K lbs) The truck also ran 15.8 in the 1/4 mile even with a very mushy shifting E4OD.

 

you arent figuring the weight and rotating mass of a hd truck. so a coyote isnt going to get that kind mpg in a hd. neither will a ls. i had hd 6.0 chevy with the 6l90e trans it got 12-13 mpg on a good day. it had great power. i also looked at a 6.2 f350 before i bought it. about 13 is best you could get and it was a lacking on power vs the chevy. idk what gears the ford had however. 25 mpg spinning 6 lug axles with a light duty trans ina 4800 lb truck is alot different than a 7k truck spinnin 8 lugs through a hd trans. go ahead knock 10 mpg off it and also it will prob feel gutless in that truck. if not ford would have ran the 5.0 and chevy would have dropped the 5.3 in the hd truck. now the dodge hemi is pretty good in a hd truck powerwise but gets alot less mpg. there is a reason the big blocks dont really get worse mpg in a hd truck. 6.0 8.1 chevy all got about the same mpg. the 350 and 454. 351 460. 5.4 and the v10 or the 6.2. in fact the 6.4 hemi gets better than the 5.7 in a hd ram. weight needs torque. so i think you could take a 6.0 for example put it in a older hd truck being its lighter with a good tune and free flowing exhaust few other mods like that and get maybe 15-16 on the highway but thats use the newer trans. idk if thats worth that money and work to you. idk how bad the 460 is. i mean if you can get 12-13 out of it. do some mpg improvements and get a few better. be money better spent. i know if a 460 truck that would be my route.

 

I'm getting about 10 - 11 with the 460 right now. I could probably regear it to 3.55 and put a 5 speed in it essentially for free when compared to an engine swap (with an engine swap I'd probably be regearing and putting a manual trans in anyway, in addition to the cost of the engine swap). And yeah, I could probably get 12 - 13 mpg from the 460 like that (empty, 60 mph highway). There's no question that would be my cheapest route. Put the thousands of dollars an engine swap would cost in the bank and use it to pay for gas. The thing is (and I know I'm not being reasonable here) To some extent I don't really care about the cost of the swap. I mean, money doesn't grow on trees in my yard either, but more than saving money with this, I'm looking to get a truck that I feel better about driving around my tree-hugger friends. Because i care about the planet too, and I just don't want to be driving a gas-hog truck, even if it's the cheapest option.

And yeah, I get that a 3/4 ton crew cab with 23 year old aerodynamics won't get the same mileage as a 1/2 ton truck with new aero design. But I'm talking steady-state highway driving, not stop-and-go, so the weight isn't as much of a penalty as it might seem. And I'm talking 60 mph. not 80, so the aero isn't quite as big either. I'm still not going to get the same mileage, but I don't think it's going to be 40% worse either (take 10 mpg away from 25 mpg).

And as far as a newer trans helping mileage a lot, I don't think that will make much difference, especially in highway driving, over a 20+ year old 5 speed manual.

The Coyote might be classified as a mod motor. But from what I've heard (which I'll only trust so far) its power curve is NOTHING like the 5.4L V8 or the 6.8L V10s that I've driven. Those are the engines I want to stay away from. If the Coyote can hold overdrive with 3.55 gears at 70 mph on level ground in a headwind it beats the mod motors I've driven.

The 351 with good heads certainly intrigues me. That's something I've thought of for a while. I know a stroker is good for torque. What's it do for mileage (if you keep your foot out of it)?

Forced induction isn't really on my radar. i know you can get a nice flat torque curve that way which is great for driveability and power. But it's a complication that I don't really want to buy into.

And that word, "complication", probably applies to a Coyote swap as well. Either the built 351 (which would go in like it belongs there) or an LS (which has tons of people putting them everywhere) would be a lot simpler.

Anyway, I'd still appreciate hearing peoples thoughts.

 

The 5.0 has variable cam timing, which is a far cry from the 4.6 and 5.4. With the ability to move cam timing to advance/retard them for the peak power level at every rpm. You just can't do that with any other engine. That with 10 spd transmissions, you are always in the powerband and using the least amount of fuel doing it.

A vortech supercharger isn't complicated. I put mine system on in one weekend. The hardest deal at the time was getting the passenger valve cover off to install the return line fitting in the front. The air pump line was in the way and that took most of the day to get apart, cover off, drilled/tapped and reinstalled. The rest was simple bolt on stuff. Since it runs off engine oil, it worked just fine for the couple years of daily driving/towing I used it on before trading it in on a new '99 V10 F350. I kept my stock exhaust manifolds, cats and installed a big turbo muffler. Had a great rumble. I wanted to upgrade things, but a new truck came in the picture so I left it alone.

I agree, the new 10 spd transmissions aren't going to make much difference in mileage.

How about this. Find a Gear Vendors OD? You could bolt that in and gain a nice drop in highway RPM which would help with mileage. You need to find the sweet spot in the RPM range that the 460 works the best. Maybe time to install a vacuum gauge and do some monitoring? See how fast it goes and how much throttle it takes to keep speed.

Have you done any tweaks to your 460? I cut the restrictor(noise suppressor) out of the inlet pipes, that plastic coupler in the middle between TB and air box. I also upped timing to 10* instead of 6*. That really woke it up before installing the supercharger.

 

My experience with a LS told me they are not a low RPM torque engine,I needed to haul a car home from Florida and rented a truck and trailer and it was a slug coming through Tennesee and Kentucky and no way would I ever use one if low end torque is needed.

 

Look at what it takes to put the Coyote ( or any Mod motor really ) into an OBS. They remove literally HALF of the engine crossmember to get the thing to sit down in the frame low enough. they will then drop onto Factory 302/351W engine perches with a little finesse.. Autofab makes some nice looking LS engine mounts which take place of the perches for $280

 

351 good heads, low end cam, and tune it, done with install sooner, and you enjoying your new 5-speed Stump Puller, even if you went with a smaller stroker 383, 393, instead of 408, it would help keep torque down where you want it. guys at work must drive the dog snot out of their F150 coyote's they running around, 15-16mpg/hiway and my 177k 351w hangs around 12-13mpg/city,

 

Hey. No answer or suggestions for you. Just an FYI on GM engines for you.

LS gets used a lot for GM’s newer engines, just in case you didn’t know, thought I’d pass it on in case you’re looking around or thinking about using one.

LS engines. There are several versions - these are the 2 most typical when people are talking about them - there are as many versions of the LS at this point as there were versions of the original small block Chevy engines. Different displacements, heads, etc etc. There is a whole series of L engines.

LS1 5.7 litre / 350 cu in. Aluminum block and aluminum heads. Built for performance.
LS2 6.0 litre / 364 cu in. Aluminum block Aluminum heads - built and tuned for performance. Corvette etc.

The other L series are completely different from the LS series.

LM 5.3 litre / 323 cu in. Your typical half ton, Tahoe, Yukon engine.

LQ4 6.0 / 364 cu in. Cast iron block aluminum heads. Truck engine. Build for lower end tq and working. Tough engine. Block and heads are different from LS. Lower flowing. Same as the older 350’s etc with different heads. Same displacement as LS.
There is an LQ9. Different pistons. Rare. It was considered the HO LQ engine.

 

There are a few more than that. LR4 ( 4.8L ) , L59 ( 5.3L Flex Fuel. Little more hp ). The Trailblazer SS had an LS2 from the factory. The LQ9 came in the Excelade and other high end big SUV's.

Little time in the junkyard and you'll find one for $2-500 with no trouble. It's also good to know the head casting numbers. Might find a 6.0L in a 1500. Can't spot it unless you look at the heads ( 873/317 for LQ4 ) (862 and 706 for 4.8L/5.3L )

Also note, the 4.8L is a slightly de stroked 5.3L. They share all but the crank. So you can spin one a little harder to do the same thing as a 5.3L

 

The Coyote is sounding less like something I want to mess with. Since everything's just spit-balling right now I wouldn't say it's completely off the table. But it wasn't really a front-runner in my mind before, and I'm not hearing anything here to move it up the list.

To answer Freightrain's question, my 460 is stock. When I bought it about 60K miles ago I did the famed "6 liter tuneup" (coil, plugs and wires with bigger gaps in the plugs). I advanced the timing as much as I could without getting knock, which put it at about 14 deg (it was at 8 deg when I picked it up). That, along with replacing some broken vacuum lines brought the mileage from about 8 up to about 10.

I have thought about a Gear Vendors OD, and I might go that route. Or I might just regear the axles. But I do plan to drop the revs one way or another.

It sounds like I need to keep looking into the LS engine(s). Yes, I knew there were a bunch that fell into the broad bucket. It would be something like the 5.3L or 6.0L truck motors that I'd be thinking about. And if they don't have any better bottom end torque than my 5.4L or 6.8L I'm not going to be happy. But hey, that's why I'm asking questions now!

 

As a purist and a Ford one at that, I can't even consider an LS. Not hatin on the Chebby guys. The Coyote is also off the table, the cost is astronomical and mine is still climbing. You would never re-coup your investment for the sake of gas mileage. The Coyote is swapped for something to do by those like myself that have no basis other than we can. If down the road you HAVE to do a swap then you should swap in the new 7.3 Godzilla into your truck. Smaller footprint than the Coyote, with a tune you have 600HP and 500TQ and a Ford in a Ford. The cost should be less than the Coyote and more suited for a truck like yours.

If it were myself. I'd put 3:73's in it and call it.

 

My truck got 10 mpg daily driving around town with some highway mixed in getting to work It got 7 mpg pulling my trailer. So you are in the ballpark of "normal". I don't recall any mileage increase with boost? But it surely accelerated easier even with just 1# of boost just driving easily around town(boost gauge barely moved). When I traded the truck in, I removed the vortech. It was like someone took 100 hp away? It was a complete slug around town. I was amazed at the major improvement that it made off idle.

I'm curious as to what the powerband is like in those old motors? Would taking gear out help? Like I mentioned above, my current F150 has 3.08 gears and it's horrible on the highway(and around town) compared to my previous truck with 3.31 gears. My big question is would just adding a GV unit help enough to warrant it? It would be about the easiest upgrade compared to a full blown motor conversion. I don't see a stroker Windsor helping that much? The only thing it would have going for it would be better flowing heads, but in a low rpm/torque application I don't see that as much of an improvement.

Were those 460 roller cam? Maybe a cam change would increase power slightly at lower rpm, that with the GV might get you enough improvement to be notable? Get up to 15+? that would be a 50% increase and I think the simplest fixes. Maybe headers and free flowing exhaust?
GV is $2500
cam $400
headers $700
exhaust $700
total $4300