Motor home 440, can they make decent power?

[Paul G]

I have brought home a 78 MH 440. supposed to have 54000 miles on it. I pulled the plugs and looked in the cylinders with a camera. They all look decent with good cross hatch. The valley area is clean as is the rockers areas, looks like new. The engine oil is clean, coolant that spilled was green, PS fluid that spilled was even clean.

I will get the engine started in the next few weeks just to see how it runs. I know these have very low compression. So what can they actually do HP and TQ wise with bolt ons like aluminum heads, cam swap, intake, carb, and LT headers, while leaving the bottom alone?

[myk]

Look into the "proven engine combos" section.  There's a thread called "dynoing a low compression 440" or something and it has to do with the build up and testing of a motor like yours.  You'll find something in that section...

[Midnight_Rider]

Look into the "proven engine combos" section.  There's a thread called "dynoing a low compression 440" or something and it has to do with the build up and testing of a motor like yours.  You'll find something in that section...

This one?:
http://www.dodgecharger.com/forum/index.php/topic,104749.0.html

[justcruisin]

If it was me and I had a limited budget, I would put the money I had into the short block and add heads etc as money allows. Either that or just run it as is and save for the whole build.

[myk]

Look into the "proven engine combos" section.  There's a thread called "dynoing a low compression 440" or something and it has to do with the build up and testing of a motor like yours.  You'll find something in that section...

This one?:
http://www.dodgecharger.com/forum/index.php/topic,104749.0.html

That's one of them.  That entire pinned section is full of 440 buildups...

[R/T1968R/T]

Take a look  http://www.dodgecharger.com/forum/index.php?topic=104749.0

[68CoronetRT]

Running the cast crank and stock rods in mine(78' motor home engine). Just added forged Speedpro pistons. It's got aluminum heads(ootb Stealth's), Lunati voodoo cam, TTi headers, holley intake, aluminum waterpump/housing and Sniper EFI w/ holleys distributor for timing control on the fly. It runs pretty good and I'm guessing around 500hp at the crank(I still think I have a cam degree-ing problem). All this and I have around 7k miles on the engine of mostly cruising with the occasional track day.

The biggest thing is getting the block decked to bump up that compression.

All the research I've done says dont cross the 600hp mark on a stock bottom end.

[BSB67]

Running the cast crank and stock rods in mine(78' motor home engine). Just added forged Speedpro pistons. It's got aluminum heads(ootb Stealth's), Lunati voodoo cam, TTi headers, holley intake, aluminum waterpump/housing and Sniper EFI w/ holleys distributor for timing control on the fly. It runs pretty good and I'm guessing around 500hp at the crank(I still think I have a cam degree-ing problem). All this and I have around 7k miles on the engine of mostly cruising with the occasional track day.

The biggest thing is getting the block decked to bump up that compression.

All the research I've done says dont cross the 600hp mark on a stock bottom end.

Can you share your track results?  You can determine HP from track data.  What track and car weight are also useful.

[myk]

Running the cast crank and stock rods in mine(78' motor home engine). Just added forged Speedpro pistons. It's got aluminum heads(ootb Stealth's), Lunati voodoo cam, TTi headers, holley intake, aluminum waterpump/housing and Sniper EFI w/ holleys distributor for timing control on the fly. It runs pretty good and I'm guessing around 500hp at the crank(I still think I have a cam degree-ing problem). All this and I have around 7k miles on the engine of mostly cruising with the occasional track day.

The biggest thing is getting the block decked to bump up that compression.

All the research I've done says dont cross the 600hp mark on a stock bottom end.

But once you've made internal modifications, it's not really a "motor home" motor anymore, right?

[Kern Dog]

The biggest thing is getting the block decked to bump up that compression.

All the research I've done says dont cross the 600hp mark on a stock bottom end.

The deck height of the 440 is the same whether the engine was from a Motor home or a Charger. If you mill the decks too much, it creates other problems to chase. Choose the right pistons with a taller compression height and the deck only needs to be milled enough to get a good gasket seal/

[68CoronetRT]

Running the cast crank and stock rods in mine(78' motor home engine). Just added forged Speedpro pistons. It's got aluminum heads(ootb Stealth's), Lunati voodoo cam, TTi headers, holley intake, aluminum waterpump/housing and Sniper EFI w/ holleys distributor for timing control on the fly. It runs pretty good and I'm guessing around 500hp at the crank(I still think I have a cam degree-ing problem). All this and I have around 7k miles on the engine of mostly cruising with the occasional track day.

The biggest thing is getting the block decked to bump up that compression.

All the research I've done says dont cross the 600hp mark on a stock bottom end.

Can you share your track results?  You can determine HP from track data.  What track and car weight are also useful.

1/4" mile I did 12.88 @ 108mph, leaving the line at 2k RPM because the brakes were leaking, so I didnt get a good launch. My 1/8 mile time was 8.3 that pass. Also at like 4,300 DA or something crazy. Motor was starving for air.

My local track is 1/8" mile and since I've sorted out the brake issue I've gone 7.94 @ 87 mph? I believe. roughly 1,700 DA.

Full weight 68 Coronet, minus the spare/jack in the trunk. So like 3,800-4,000 lbs maybe? I forgot to weigh my car when I was at the 1/4 mile track.

[68CoronetRT]

Running the cast crank and stock rods in mine(78' motor home engine). Just added forged Speedpro pistons. It's got aluminum heads(ootb Stealth's), Lunati voodoo cam, TTi headers, holley intake, aluminum waterpump/housing and Sniper EFI w/ holleys distributor for timing control on the fly. It runs pretty good and I'm guessing around 500hp at the crank(I still think I have a cam degree-ing problem). All this and I have around 7k miles on the engine of mostly cruising with the occasional track day.

The biggest thing is getting the block decked to bump up that compression.

All the research I've done says dont cross the 600hp mark on a stock bottom end.

But once you've made internal modifications, it's not really a "motor home" motor anymore, right?

Yea, once you ditch the rotating assembly and deck the block it's the same as any other 440. I've heard rumors that the motor home engines had better webbing for block strength but that sounds like snake oil to me.

[Paul G]

I have not opened the engine up yet, but I have read that the motor home engines have better rods. Is that true?

When I do get it torn down it would be great to find the cylinders in great shape, I suspect a slight overbore will be necessary, true up the block, and install lighter higher compression pistons. My plan is to use the Trick Flow PP240 heads OOTB, Eddy dual plane intake, Holley 850, and then pick a piston and cam. Should not be too hard to hit low to mid 500HP/TQ seeing that Bob has done that already with his "lowly" builds with stock stroke engines using his experienced porting on a  set of source heads. The PP240 heads are CNC'd, no need to send them in for port work. 

[Paul G]

Short video of the engine running. Could not run long since I just filled the bowl and let it run out of gas. It made over 60 psi of oil pressure, the 60 psi gauge was pegged.

https://photos.app.goo.gl/MDJXH443p2rh3Q183

[myk]

I heard the motor home 440's had better cooling passages designed in them too, or something...

[BSB67]

1/4" mile I did 12.88 @ 108mph, leaving the line at 2k RPM because the brakes were leaking, so I didnt get a good launch. My 1/8 mile time was 8.3 that pass. Also at like 4,300 DA or something crazy. Motor was starving for air.

My local track is 1/8" mile and since I've sorted out the brake issue I've gone 7.94 @ 87 mph? I believe. roughly 1,700 DA.

Full weight 68 Coronet, minus the spare/jack in the trunk. So like 3,800-4,000 lbs maybe? I forgot to weigh my car when I was at the 1/4 mile track.

That is real good performance.  Few guys can actually post those kind of numbers.

So here is what the numbers translate to:  Approximately 450-460 gross flywheel hp.  That is from using mph, 4000 lbs, adjusting to std conditions, and a general assumption for adjusting from net to gross.

Don't be fooled by all the 500 hp talk that is out there.  A lot of happy dynos.   110+ mph in a true street car is very good in my book.

[BSB67]

I have not opened the engine up yet, but I have read that the motor home engines have better rods. Is that true?
 

Define better?  They are heavier, and most people would say they are less desirable because of their weight.

[68CoronetRT]

That is real good performance.  Few guys can actually post those kind of numbers.

So here is what the numbers translate to:  Approximately 450-460 gross flywheel hp.  That is from using mph, 4000 lbs, adjusting to std conditions, and a general assumption for adjusting from net to gross.

Don't be fooled by all the 500 hp talk that is out there.  A lot of happy dynos.   110+ mph in a true street car is very good in my book.

Thanks! it has been an experience. My first real motor build from the ground up. For a full weight street car it can hang with just about anybody I come across.

Of course when I go to the track I feel so slow. But I also realize I'm not trailer-ing it to the track. I'm driving there on my drag radials, air downing and sending it, airing the tires back up and driving it home.

[c00nhunterjoe]

That is real good performance.  Few guys can actually post those kind of numbers.

So here is what the numbers translate to:  Approximately 450-460 gross flywheel hp.  That is from using mph, 4000 lbs, adjusting to std conditions, and a general assumption for adjusting from net to gross.

Don't be fooled by all the 500 hp talk that is out there.  A lot of happy dynos.   110+ mph in a true street car is very good in my book.

Thanks! it has been an experience. My first real motor build from the ground up. For a full weight street car it can hang with just about anybody I come across.

Of course when I go to the track I feel so slow. But I also realize I'm not trailer-ing it to the track. I'm driving there on my drag radials, air downing and sending it, airing the tires back up and driving it home.

How low are you airing them down? My drag radials hooked their best at 27 psi on my car.

[68CoronetRT]

I run them on the street at 26 psi and they actually hook up fairly well. At the track I run about 16-18psi and it hooks pretty hard. The last time out they dead hooked I think, it felt like the axle broke. I peddled it and got back in it and it ran straight with no axle noise. I only have about 10-15 times down a track in my life and have never ran slicks, so I'm pretty new to the game.

I dont even do burn outs properly....   Too scared to break parts I guess. It's the way I was raised, if your car broke down you dont go to work, which means u cant earn money. My friends tease me all the time for not beating on my car, but it's my car and I like things to last! haha

[BSB67]

My experience with a street radial is if you leave the same tire on the car for both street and track use, you're better off picking a pressure and leaving it there all the time.   This way you always have an evenly loaded contact patch.  This was true for BFG T/A radials.  No direct experience with this on M/T, but would think the results might be the same.