MOPARians, step on in and solve the mystery.

[DRTDEVL]

I have an old RV, a 1980 Winnebago Minnie Winnie 20RG. It sits on a 1979 Dodge Sportsman MB400 chassis. It has a 5.9 gas motor, of which I always assumed was an LA-360. Someone pointed out the distributor was in the wrong place for that to be the case, and I began digging, only to figure out that this is a B-361.

So the B-361 was discontinued in 1978. The chassis is from 1979. The RV is from 1980. The RV was sold in CA with CA emissions, although the weight classification didn't require a catalytic converter, and it is fed by a Cater Thermoquad at 800 or 850 cfm (probably 800).

What I am trying to figure out is the HP and TQ ratings of this engine in this configuration. Most information about them ends in the late 60s and early 70s, when it was no longer used in the regular pickups and became a bus, RV, and industrial engine application. Most of these applications had 2-bbl and small-ish 4bbl carbs on them, thereby negating their ratings (along with being the gross, not sae net ratings) Sometime in the future, I am going to rig up a 47RH behind it, rather than the 727, with hydraulic switches controlling the functions of OD and lockup, but I need to figure out the torque output in order to get the right build and torque converter ratings. After all, what good is converting something if its only going to blow up the first time I tow heavy behind the RV?



EDIT!!!!! I pulled the illegible data card and scanned it in so I could play with the contrast and brightness to read it. Apparently, grandpa got it wrong the entire time. It is a 440-1 (a higher output RV-specific version). The regular 440s had 195/300 in cars (with a 2-bbl carb) in 1978, but does anybody know the RV-specific 440-1 ratings? They were last built in August 1978, so the rest of the post's confusion is true.

 

[Aisin]

Late 70s smog shit box? 180 horsepower at the flywheel probably. Does it really matter what kind of power it makes?

 

[DRTDEVL]

Late 70s smog shit box? 180 horsepower at the flywheel probably. Does it really matter what kind of power it makes?

HP isn't the important number, TQ is. These engines came in configurations placing them over 400 lb-ft, even with small HP numbers, based upon their design.

A 1994 Ram Cummins had 160 hp and 400 lb-ft of torque from the factory, and we all know what happened if the owner turned up the fuel at all on that OEM 47RH... so yeah, it DOES matter how much power it makes.

 

[Aisin]

HP isn't the important number, TQ is. These engines came in configurations placing them over 400 lb-ft, even with small HP numbers, based upon their design.

A 1994 Ram Cummins had 160 hp and 400 lb-ft of torque from the factory, and we all know what happened if the owner turned up the fuel at all on that OEM 47RH... so yeah, it DOES matter how much power it makes.

Comparing a late 70s smog motor to a Cummins is quite stupid. Your clapped out 42 year old engine with 300,000 miles probably makes less power than a 4 cylinder Camry.

 

[DRTDEVL]

Comparing a late 70s smog motor to a Cummins is quite stupid. Your clapped out 42 year old engine with 300,000 miles probably makes less power than a 4 cylinder Camry.

27,000 miles. Crossed that milestone on the return trip from Sturgis last month.

 

[DRTDEVL]

I'm going to edit the original post, as I found new information.

 

[montrose818]

400ft/lb? not happening.

If you want to be safe, Id guess 330 ft/lb tops, ever.

 

[bigun]

It is an orphan like my 413 it's a Mopar BB but no one has any current information on it or make parts for it.
You might look into swapping in an 440 IIRC it should be a bolt

 

[Aisin]

The highest output 440 for 1978 was 255 horsepower. Those were only available in police cars.

 

[Rockbuggy84]

Why don’t you just go and put it on a dyno?

A 40 year old engine, low miles or not is not going to be at factory spec.

My guess on your results-110 rwhp and 220 lb ft

 

[Norm]

Dodge sold a bunch of left over 78 440’s to the rv industry , they were low compression (7.5-8.0 range). 200 hp /340tq wouldn’t be too far off as a high guess. There were a ton of those sold in 78-80. Cam and heads would really wake it up. Those low compression smog motors were really neutered.

 

[HillbillyDeluxe]

Better build that 47rh with billet input and output shafts, cryo'd sun gear, the most hd clutches available and a billet triple disc converter.

Just in case.

 

[[486]]

HP isn't the important number, TQ is.

Saying shit like that you've just gotta cummings swap it brah then you'll be making 30 gallons per mile especially if you also put on some cummings brand cummings logo cummings official window stickers on it and stacks and tow mirrors atop your tow mirrors

 

[Elwenil]

200 HP/320 ft lbs

 

[78bronco460]

I’d work up a set of 1960’s 383 closed chamber heads with some oversized valves (2.14i/1.74e), hardened seats and silicon guides. Get a cam and valve springs with lift, 440’s like lift.

 

[bradp674]

LS swap is always the answer.

 

[2big bronco]

Shouldn't you be able to get close on to with hp and rpm? Have your trans built for 200/300 but really you are over thinking it.

Putting it on a dyno would probably be a funny water of $60 and get you exact numbers. I'm guessing 118/200 ish.

Also isnt that the same motor/trans roadkill used in the samurai? It seems like they rattled off some numbers

 

[Elwenil]

Shouldn't you be able to get close on to with hp and rpm? Have your trans built for 200/300 but really you are over thinking it.

Putting it on a dyno would probably be a funny water of $60 and get you exact numbers. I'm guessing 118/200 ish.

Also isnt that the same motor/trans roadkill used in the samurai? It seems like they rattled off some numbers

906 heads are good, but the heads he has flow about as well, just with hardened seats and a larger chamber. The compression is easily fixed with some new pistons or some machine work.

At the end of the day, the 727 stood up to 1 ton trucks with big blocks, 440 magnums, 426 Hemis, etc, so unless you are building to that power level, leave it alone and focus on cooling.

 

[DRTDEVL]

At the end of the day, the 727 stood up to 1 ton trucks with big blocks, 440 magnums, 426 Hemis, etc, so unless you are building to that power level, leave it alone and focus on cooling.

I'm not looking to build for more power, I am looking to replace the transmission with an OD unit, like a 47RE. The only power adders I am interested in are ones that increase fuel economy, and thereby usefulness of the RV. I already had a custom exhaust built to replace the 2.25 or 2.5" single pipe that was there with a 3" that runs all the way to the rear with a side exit, rather than exiting right behind the tire (below the fuel filler neck, a very dangerous place). That brought it from 6 mpg to 8 mpg alone. This fall, I would like to put a FiTech TBI system on there to clean up its running and increase economy by keeping it closer to stoichometric under all conditions. Hopefully that will get it to hit 10 mph. Next year is when I plan the transmission change in an attempt to hit 12-14 mpg (and potentially 10 when towing).

It only has 27,000 miles on it, so the engine is nowhere near tired. It can toss everything off the dinette table when leaving a stoplight with a touch too much throttle due to the relatively high torque output combined with 4.10 gears. I have little use for more power, but massive interest in more fuel economy (I know, I know, make a custom doghouse and shoehorn a 12 valve in there... not gonna happen).

 

[Elwenil]

I'd just stick a 46RH in there, built to normal 360 specs and let it ride. Keep it cool and don't turn the overdrive on until you get to 45 MPH.

Also be aware that your 440 is a cast crank version, so you will need to balance your new torque converter to it. A 360 spec converter will have different balance weights.

 

[Jackie Treehorn]

An rv motor should have an rv cam which is good for an extra 100 horsetorques according to a guy on Facebook.

I’m sorry, your 7.5:1 smog motor isn’t making 400 ft lbs.

 

[[486]]

I’m sorry, your 7.5:1 smog motor isn’t making 400 ft lbs.

I'm sure it's got like 4:56s or 5.13s, so it's probably making 400 ft/lb ...at the wheels

 

[LSxFJ]

This fall, I would like to put a FiTech TBI system on there to clean up its running and increase economy by keeping it closer to stoichometric

If your gonna go TBI, go Holley Sniper.

 

[TRINDU]

I'm at the fact you think 12-14mpg from a 440 powered RV is plausible.

 

[grumpy356]

HP isn't the important number, TQ is. These engines came in configurations placing them over 400 lb-ft, even with small HP numbers, based upon their design.

A 1994 Ram Cummins had 160 hp and 400 lb-ft of torque from the factory, and we all know what happened if the owner turned up the fuel at all on that OEM 47RH... so yeah, it DOES matter how much power it makes.

Hp or Torque, the numbers mean nothing.

It’s how it feels. Block the numbers from your mind, and feel if it is enough.

 

[Norm]

An rv motor should have an rv cam which is good for an extra 100 horsetorques according to a guy on Facebook.

I’m sorry, your 7.5:1 smog motor isn’t making 400 ft lbs.

Small chamber heads would bring the compression up to 8.5:1, rv cam, carb, exhaust together would probably add 100. Just a cam would be 25-30 hp.

 

[bigun]

Small chamber heads would bring the compression up to 8.5:1, rv cam, carb, exhaust together would probably add 100. Just a cam would be 25-30 hp.

Your going to spend $1,200 for a set of aftermarket ones, I have been looking the 413 short block I picked up has dished piston. Right now it's just sitting on the stand because no one makes pistons for it, and finding 415 heads in NM is not happening

 

[evernoob]

The only power adders I am interested in are ones that increase fuel economy, and thereby usefulness of the RV.

This post is for me, it's nothing more than standard efficiency talk b/c I needed something to do while watching Tucker Carlson.

The only variable in the thermal efficiency of a 4-cycle gasoline engine (Otto Cycle) is compression ratio:

'k' = Specific Heat Capacity of air, an intrinsic property which can be considered a constant.

All 'breathing mod' to an engine are in some way to put more air/fuel into the engine, while at the same time optimizing the dynamic compression ratio (the ratio of actual compression given from intake valve closing to TDC.

Increasing the compression ratio and using FI and ignition timing to prevent detonation are the best ways to increase efficiency. And, in light of the Thermal Efficiency formula, the only way. Intake and exhaust modifications, and cam profile and timing, increase efficiency by increasing the effective dynamic compression ratio by allowing the cylinder to more fully exhaust, and the more fully fill.

Of course, most power mods are made with the idea of consuming more AF mix per unit time, giving more power. However, the increase of efficiency of a high-compression, well-breathing motor is considerable, and if the engine is built to provide good manifold vacuum over a broad RPM and throttle envelop, the right foot will ultimately determine the overall fuel efficiency of the system.

To increase fuel-efficiency in a high-utilization engine:

• Increase Static Compression Ratio
• Prevent pre-detonation via EFI with ignition timing control (and good air-flow characteristics, see below)
• Use a high-lift, low-overlap cam profile with middling-to-low duration (edit: you can also promote torque production and help close the intake faster by advancing the cam timing).
• Facilitate airflow by port-matching and providing moderately well-breathing heads and intake/exhaust piping.

That is the formula, and it will never change.

To speak to the last point:

• Smooth and moderate air-flow prevents hot-spots, lean cylinders, and other inconsistencies for pre-detonation events to start
• Exhaust piping as large and free as tolerable is better, no exceptions
• Single-plane, low-rise, open-plenum intake manifolds work best on low-to-moderate RPM V8 engines with throttle body injection (Victor Jr.) Avoid dual-plane intakes which create mixture inconsistencies to outlying cylinders; dual-plane manifolds are purely designed to present a simulated consistent vacuum signal to carburetor venturis. Single-plane, air gap intakes have the knock-on effect of cooling the AF charge as much as possible, thus presenting the greatest heat difference possible in the cylinder, thus increasing efficiency (and power), thus increasing gas mileage.

Modern cars run 10.5:1 CR+ at this point. That's because CR is the only variable in the thermal efficiency of an Otto heat engine, and all other factors serve the CR.

A typical Otto gasoline engine will run below 40% efficiency (Toyota is claiming a 41% TE on a naturally aspirated engine, this is a special case). Therefore paying attention to TE will provide the greatest gains in fuel mileage, given equal attention to the right foot.

 

[evernoob]

I am clearly not a MOPARian, Edlebrock does not make a Victor Jr. for the 440. They make a plain-Jane Victor which looks perfect for a TBI setup. $364

If you are the average fabricator around here, you could probably make one just as good.

 

[DRTDEVL]

I'm at the fact you think 12-14mpg from a 440 powered RV is plausible.

Meh.

When I first drove it, I got 6.5 mpg. When I changed the exhaust and put modern (taller) tires on, I got 8... Its not that far-fetched to believe that someone with over a quarter-century of professional driving could eek out such numbers... after all, I just hit 8 with a carbureted 440 and a non-lockup, non-overdrive transmission in a 9,000 lb brick on wheels. I got 6.5 on the way to Sturgis with a 7x16 enclosed trailer containing a bunch of gear and a pair of touring Harleys inside. I got 7.5 with a car hauler pulling a 70's Buick on it.

Its all in driving style.