Motor Home 440 engines

[grizzlygiff]

I was wondering if anyone here has used a 440 from a motor home for their project? There is one here local with less than 2K original miles for $750 with transmission included. Supposed to run well and has a thermoquad 4 barrel. 1978 year model. I know that it probably has low comp pistons, but this seems like a good deal for a running engine. Was wondering if there was any reason to avoid these engines. This would be replacing a tired 383.

[tricky lugnuts]

Like you said, low compression, probably a cast crank are the obvious drawbacks.

I think I've heard some of the motor home engines also have unusual cylinder heads, exhaust and intake manifolds that might not work so well in your application, so you might need to replace parts along those lines, too.

Not sure about bolt on accessories like power steering, alternator, or air conditioning.

Otherwise I assume the motor home engines would be just like any other 440 engine.

With less than 2K original miles it could certainly be a good bottom end to build. Maybe you could deck the block or trim the heads to bump up the compression without swapping out pistons. I'm not sure...

I'm not sure about the motor home transmissions either, whether they're a typical 727 or if there is anything unusual or problematic about using them in a passenger car application.

[Chatt69chgr]

Good 440 blocks go for 300-700 depending on where you live.  If the block you are looking at was not overbored at the factory and has nice engine mount ears and nothing else is broken on it, then I'd say that you have a nice block to start your build with.  Trash the rotating assembly and buy one from mancini.  They have the eagle crank, eagle rods, and diamond forged pistons.  You can have the short block built "0" deck and then add Edelbrock 84CC aluminum heads, and 40-45 thousands head gaskets to yield a nice 10.2:1 CR street engine.  Comp cams can help you choose the proper cam for you application (and to keep the dynamic compression ratio down).  Add a dual plane aluminum intake, some headers, and you will have a real nice street engine.
The tailshafts in automatics are different I think.  Don't know about the rest of the tranny.
I think the exhaust manifolds are different on motor homes---toss and use the headers.
So, if you buy this, you are essentially buying a block.  Offer $300 since you really don't know if there is cylinder wall damage or not.  If you can examine the cylinder walls and they look good, might offer more.

[ih8gmandford]

 Make sure it's a 1978 440 and not a 1978 413. The 413 has nothing that can be used in a 440 except the rods and possibly the crank. The block is different as are the heads. There are no exhaust manifolds or headers designed to install the 413 in a passenger car, so you're out big $$. Very low compression. If it were earlier I'd say nab the thermoquad off of it.
  I traded a GMC van for a 440 out of a 1975 RV. Turned out it was the 413... -Jason

[SRT-440]

Got a '77 Motor home 440 in my 71 dart...we replaced the rotating assembly and put a new intake, carb, cam, headers, six pack rods and pistons, forged crank. Also used the 727 that came with it..had it rebuilt. Runs great.

The biggest thing is getting the compression up cuz it's loowww..LOL.

[200MPH]

i had a motor home 413 it was a 78 but it had the regular heads and water pump assembly on it

[69DodgeCharger]

That's a $350 engine complete and running around these parts. You'll see guys asking 800-1,200 for them on Craigslist....For months on end until the finally come down into the 3-4 hundred range then they disappear. The tranny on the 440 I got out of a 79 Titan Champion was a shortshaft.

[grizzlygiff]

Thanks for all the replies. I'm probably gonna pass on it. I might just rebuild the 383. This will be the second rebuild on it. I did it the first time in 1985 at age 17. Maybe this time it will last! LOL

[beachbum52]

I see most guys here have little to no data on the motor home 440's. They are a low compression engine , however, it is a great engine for a blower or turbo. These engines carry a 440-3 designation. It is an industrial/marine engine. Most have an 8.5:1 compression ratio but some had as high as 9:1 down to 8:1. the bottom ends are awesome! forged crank, forge pistons and super duty rods.
The heads and block are a bit different than the automotive block. There is an extra coolant port in the block and heads for extra cooling efficiency. Automotive performance heads will bolt on to the block but will block the extra coolant port.
I have been using these engines in performance boats for over 35 years. Back in the day I used roots style blowers with a pair of 850 holley carbs a high pressure regulator that increased fuel pressure in parallel with manifold pressure , opened up the heads with porting and BIG valves. I made my own solid copper head gaskets and steel "o" rings in the heads and block.
The cam should have between 4 and 7 degrees more lobe separation than a normally aspirated design cam.
I still run the same basic setup, except now in the electronics age, I use an aftermarket programmable engine management system, electronic fuel injection, and twin turbo chargers.
I only run 10 psi max boost (running 93 octane pump gas) and produce around 950 plus hp at 6400 r.p.m. with a stock bottom end torque curve is very flat 762 ft. lbs.@ 2800 to peak at 840ft. lbs  @ 6300 r.p.m.
IMHO based on my experience with the 440-3, this engine is virtually bullet proof under 6500 rpm.
I run the same setup in my tow rig... It's a '53 Mack with a hand made 10 ft. pickup bed running the rear diff and from a 77 motor home with air ride suspension. custom built frame and  independent front suspension also bagged. Using the also bullet proof motor home 727 auto with a custom made 1600 stall lock up converter. rear gears were changed to 3.08:1. It'll cruise the interstate at 75 turning 1900 R.P.M. and sipping out 14.5 mpg.
These engines ARE awesome. they are also very cheap. I typically buy the complete ragged out motor homes for 6 to 8 hundred dollars sell off the ac units, water heaters, fridges and stoves for more than what I paid. most have less than 50K on the clock and most of the time the entire drive train is in great shape. I would love to fine a nice charger  or challenger body to put one of my engines and trannys in. anone interested in some trading?

[c00nhunterjoe]

Roadkill stuffed a late model motorhome 440 into their 68 charger and had a blast with it.....

[69wannabe]

I bought one a couple years ago for a steal pretty much, it had 452 heads on it and it was a cast crank engine. I have several steel crankshaft's if I ever need to use it so I will just make a steel crank engine out of it. The cast crank was in perfect condition tho but it has that weird big balancer on it. I have seen the odd 413 engines with the odd heads and manifolds. Someone crammed one into a 69 charger a few years back and a guy locally traded for it not knowing what he had traded for. It was running and driving somehow but it was sad how the engine was just thrown at it.....

[1974dodgecharger]

Roadkill stuffed a late model motorhome 440 into their 68 charger and had a blast with it.....

and did only minor upgrades to it like intake, headers, carb and got 385hp with like 450ftlbs....I FEEL STUPID FOR PAYING SOMEONE 8 GRAND TO BUILD MY LOUSY 383.


When you can get a motorhome 440 that produces that much power....feel like a dumbass 

[c00nhunterjoe]

Roadkill stuffed a late model motorhome 440 into their 68 charger and had a blast with it.....

and did only minor upgrades to it like intake, headers, carb and got 385hp with like 450ftlbs....I FEEL STUPID FOR PAYING SOMEONE 8 GRAND TO BUILD MY LOUSY 383.


When you can get a motorhome 440 that produces that much power....feel like a dumbass 

They did heads too on the last modification round. That was the biggest gain.

[John_Kunkel]

I see most guys here have little to no data on the motor home 440's. They are a low compression engine , however, it is a great engine for a blower or turbo. These engines carry a 440-3 designation. It is an industrial/marine engine. Most have an 8.5:1 compression ratio but some had as high as 9:1 down to 8:1. the bottom ends are awesome! forged crank, forge pistons and super duty rods.

A '78 (the OP specified '78) 440-3 wouldn't have a forged crank/pistons or the heavy rods or a CR anywhere near 9:1....nearer a true 7.7:1

A '78 did, however, have exhaust valve rotators and "auto-thermic" CAST pistons (these have steel inserts to control piston skirt expansion) in addition to the block and head differences.

[beachbum52]

 I can't address the '78 and newer engines, I've never had one. However, I have had several 440-3 engines from '70 to '77 and they all had forged cranks, the heavy duty connecting rods, and forged pistons. I have been putting them in performance boats (and a couple o hotrods) for about 35 years. The 9:1 cr motor is a marine engine. I have run several of these engines with 10 psi boost on 93 octane without problems. The cam you need is critical for good boosted performance as well as some good head work. Lunati make some great cams for this application. You will want a cam with a 4 to 7 degree wider lobe separation than a normally aspirated cam design. I run a programmable aftermarket ecu and a homemade staged fuel injection with a twin turbo system. It takes about 25k to build one of these engines with all the electronic goodies and the turbos. That's pretty cheap foe 900+ ponies that will live a long time.

[Challenger340]

I see most guys here have little to no data on the motor home 440's. They are a low compression engine , however, it is a great engine for a blower or turbo.
I only run 10 psi max boost (running 93 octane pump gas) and produce around 950 plus hp at 6400 r.p.m. with a stock bottom end torque curve is very flat 762 ft. lbs.@ 2800 to peak at 840ft. lbs  @ 6300 r.p.m.

It is possible that you could you post up an actual Dyno Sheet of the 950hp @ 6400 rpm and 762 Ft/Lbs Torque at 2800 rpm on that "stock" 440-3 motorhome bottom end at only 10 psi Boost ?

What size roots case you were using ? and the drive ratio ?
What size additional keyway you were cutting in the Crank snout ?

Thank You for your time.

[Bob T]

I see most guys here have little to no data on the motor home 440's. They are a low compression engine , however, it is a great engine for a blower or turbo.
I only run 10 psi max boost (running 93 octane pump gas) and produce around 950 plus hp at 6400 r.p.m. with a stock bottom end torque curve is very flat 762 ft. lbs.@ 2800 to peak at 840ft. lbs  @ 6300 r.p.m.

It is possible that you could you post up an actual Dyno Sheet of the 950hp @ 6400 rpm and 762 Ft/Lbs Torque at 2800 rpm on that "stock" 440-3 motorhome bottom end at only 10 psi Boost ?


And just for the heck of it, how bout some boat photos please?
I used to have a 17'6'' Flatbottom with a twin tunnel rammed 355 in it, would do 70 and a bit, lots of fun!

What size roots case you were using ? and the drive ratio ?
What size additional keyway you were cutting in the Crank snout ?

Thank You for your time.