5.2 Magnum and 727

I want to swap out the 440 in my truck for a later model 5.2 and would like to use a small block 727. What if any problems might I encounter doing this? Balance issues?

Just use a neutral balance convertor and you'll be just fine.

would be a perfect time to switch to an A518 with the overdrive.

I consider ONE the things that is required is a PCM from a manual 318.



Kodi nox

I went from LA 318 to Magnum 360 crate and correct, just remember 360 externally balanced so weighted converter or scalloped flex plate.

You probably won't see an appreciable gain in fuel milage, but for sure a tremendous drop in performance.

I assumed something wrong with the 440 for someone to take that drop in cubes

Nothing wrong with the 440. I'm just tired of getting 6 mpg. I should be able to at least double that with the 5.2. I haven't bought the transmission yet, but I have everything else I need. I can't seem to locate an A518 where I live, so I figured a 727 would have to do for now. The truck is a 77 D100, short /wide box, 3.23 gears and 28 inch tires. The 440 runs good, stock 77 engine, RV cam of some sort, was in it when I bought it, 750 Holley, headers and dual exhaust. I can't get by a gas station with it. It was okay when gas was cheap, but not anymore.

If it is solely saving money through better mpg,
a 5.2 with a stock PCM and a unlocked torque converter with a 727 is not going to be a bank account improver, nor a resale improver.

Consider converting the 440 to fuel injection.
Sequential fuel injection with a Megasquirt PCM would allow the 440 to run a very lean air to fuel ratio, which would greatly improve fuel economy, but still have far more Torque than a 318.

One of the TBI fuel injection kits would be a simpler install, but more $
These can also be run lean.

Resale value of your vintage D100 with a fuel injection 440 would be far more appealing resale wise.

Just a curiosity question: Do you (or others here) have some real world fuel injected 440 MPG numbers to share with the OP?
It might be helpful to him...

As for that 5.2 in question, my stock 2001 Ram 4X4 with a 5.2 gets right at 12 MPG. That's fuel injected with an OBD II computer. I've heard others say that theirs get better than that, but mine doesn't, and I don't beat on it.

Sequential fuel injection reduces the variation between the cylinders, with a ballpark fuel economy improvement of 8% just with that mod.

Running a “lean” air to fuel ratio of 20 to 1 dependably improves fuel economy by 25% compared to 14.7, but without sequential fuel injection to keep all cylinders even when running very lean the worst 3 to 4 cylinders will begin misfiring.

How lean can you go?
The Australian sold Honda Insight with one sparkplug per cylinder leaned out to 25 to 1 at highway cruise.

If you have a big cubic inch engine like a 440 and you want it to get nearer the highway fuel economy of a 318
you can get partway there by slowing down the RPM at highway cruise by the usual tricks:
2.76 versus 3.23 diff gears,
Gear Venders overdrive,
taller tires,
transmission with 0.5 top gear, etc.

If you get the manifold vacuum at highway cruise to 6 inches of mercury on both the 440 and 318 fuel will be converted to power at about the same.
Smaller cube engines have no “magic” .
Big cube and small cube V8 follow the same laws.

Is the engine size the only “ticket” to better fuel economy?

No.

Switching to newer design “low rolling resistance” tires is the fastest and easiest single mod.

Aerodynamic tweaks of the truck body can be achieved at surprisingly low cost,
and a D100 is way worse shape than any modern truck,
but a D100 has a smaller “frontal area” and lighter weight.

The 440 does suffer from its
high piston ring friction,
lack of “squish & tumble” in the combustion chamber design, and
slightly lower compression ratio,
compared to the Magnum 5.2 V8 under swap consideration.

A 5.7 Hemi with its twin sparkplugs and other tweaks is officially 6% better than a Magnum 5.9 V8, according to Chrysler.

There are probably a lot of small (and maybe large) things that you could do to your 440 that might improve the economy. Have you thought about trying to optimize what you have rather than change it out? Might be cheaper and easier than a swap.

Another consideration for this swap is not having to worry about wiping my camshaft. I have wiped out flat tappet cams in the past, even breaking them in correctly and using the proper oil. Having a roller takes some of that worry away. Buying a fuel injection set up for the 440 will cost more than I want to spend right now. I have the good running 5.2 for free, already have new headers, an RPM intake and a 625 Carter carb. That leaves me with a great running 440 and 727 to trade, sell or keep for another project. I'm an old ba$tard and live on Social Security, I just need a transmission.

There are a few things you can do to the 440 to get better mileage but it's not going to beat 5.2 or 5.9. I would strongly suggest to wait for a A500 or similar (46RH)! Not only overdrive but a lock up converter. The lock up converter cuts 200 rpms off when it's engaged. My power wagon has just a 727 and a 360 with 3.55 and 31's and you don't even think about getting on an express way. You will be doing 3K+ and cars will fly by you where a A500/46RE will like 1.2K and keeping up with traffic. Not to mention the gas usage difference.

The “right” transmission might be the easiest swap that yields the greatest MPG gain.

Consider selling some of the stuff you have to get a manual transmission with a low (0.5 or 0.6) top gear.

back in my junkyard days, i had a 73 4x4 that had 3.91 gears, 32" tires, and a 318/727 combo.
when i replaced the bed, i built one from 1/8" plate with a 2x12 oak floor. this bed was to be indestructible when hauling parts and scrap. [it turned out to be, as 40yrs later, the buyer of my truck still owns it, and the bed is still as i built it. ]
when it was done and installed, along with a "basher bumper" and bed roll bar made from 3" gas line piping, [not the cheapo thin items you buy on the market today, as well as back then] the truck weighed over 7000lbs.
the 318 never got any gas mileage as it was, and after the mods, it got around 5mpg.
i grabbed a 440/727 out of a chrysler station wagon, tore the 318's 727 apart for the short tailshaft stuff [the truck had a divorced transfer case] and stuffed it in my truck.
the only mods to the station wagon engine was an rv cam, and an 850cfm T-quad with an adapter to the square bore intake the station wagon engine came with. [i think the wagon was a 69 or 70 model.]
the gas mileage went instantly from 5 to 14 or so empty, to 10-12 when loaded with parts or scrap. the owner today [who bought my truck all those years ago] still says the truck gets amazing gas mileage !
i think the reason was the 440 just loafs along pulling that weight, while the 318 was foot to the floor most of the time.
just my personal experience with a 440 in a truck. your mileage will vary.

Good info.

Leaves one wondering what air to fuel ratio the OP’s carb is delivering to his 440,
or whether a wiped exhaust lobe(s) on his cam is greatly restricting cylinder(s) exhaust.

The 5.2 in my 1998 1500 2WD was a sweet package that got mid teens city and would almost touch 20 if I was nice on the highway. It was a porky truck at 5000 lbs! Been to the scrap yard more than a few times and it would tip the scale empty at 5k

It was still had very acceptable performance and I had no issues towing with it.

My '14 with hemi 2wd currently is averaging 18.7 and will get 23-25 on the highway if not driving like a lunatic. 2012 or 2013 and up Chrysler went through the trucks and improved the MPG with active radiator shutters, roller bearing rears, transmission pre-heat, etc which make a big difference.

Elmor, if you're still waiting for answers, go to http://www.magnumswap.com/

Yeah Mike, I've recently been there looking for answers using the serpentine belt set up without a/c. I was originally told that I needed an idler pulley of some sort. Found out I just need a different belt and re-route it. Thanks for
sharing the info.
Lee

Studying the fuel economy difference between the
1992 Ram Magnum 5.2 V8 and the
1994 Ram Magnum V10
is a valuable way to build knowledge.

How does engine size, gearing, aerodynamics and weight affect pickup truck fuel economy?

An (almost) silly question:

On a level blacktop highway how much of a pure tailwind speed does a
1971 4wd Ram with a 440 V8, manual trans and 3.92 diff
have to have blowing to match the zero windspeed MPG of a
1994 4wd Ram with a Magnum 5.2 V8 46RH and 3.21 diff ?

The Windows computer program “Fuel Economy Calculator”
from Performance Trends Company
is the only under $200 program I know of
that can give a plus or minus 7% answer
to that question.

The V10 had some horrific real world MPG numbers if I recall.

My 2WD V10 dually with 4.10 gears got 9 MPG pretty much no matter what except with the 30' enclosed trailer behind it, then it got 6.

You recalled correctly. I decided to with the 5.9 when i was in the market for a second gen. The V10 didn't offer MDS that's why it used so much fuel(it's 488 cubes!).

I have a stock 1974 D100 440 with 3.23 gears and 29 in tall tires and I routinely get 11-12 MPG unloaded and around 9 mpg pulling a load, with either a Thermoquad carb or a Edelbrock 800 AVS style carb, if I put an overdive behind it it would probably get around 15-16mpg.

Getting 6 mpg out of your setup is way too low, holley carbs are great peformance carbs but sometimes take a little work to get fuel mileage out of them, they are generally setup fairly rich out of the box. I had a Thermquad carb on a 440 in my 69 Charger and it would routinely get 15mpg and when I dropped an out of the box 750 vac secondary holley on it the mileage dropped to 12mpg but the throttle response and power was noticably improved.

Another area is to check and make sure your ignition timing is set right, you should be in the range of around 10-12 degrees initial timing and 36-38 degrees total timing all in by 3000 rpm (assuming you don't run into detonation problems) and make sure the vacuum advance it working, with the vacuum advance working the timing should be in the 52-56 degree range. All this can have a significant effect on fuel mileage and power.

It seems your dead set on a 318 engine but this info might help if you decide otherwise.

Kevin