Ok, coming from a guy with a 56 that hes been trying to find a way to build it as a 4x4 that gets 25mpg and can do 80mph on the freeway for over 10 years:

LEAVE THE MH AS IS.

The Cummins will break parts. It will also shake the truck like a *****. It will not give you what you want, it will not drive like the Dodge without swapping it all onto the Dodge, in which case you will be money ahead to sell the MH, buy a cab and some fenders and put it on the Dodge. Yes it's way more work than it sounds and usually results in 2 dead trucks.

If you do find a way to cruise at 80mph, and trust me I get the draw... what if you crash? These things are not designed to crash at 80mph. More like 45. Gotten it up to 45? Its a bit iffy ain't it?

The MHs are rare, they are not made out solid gold rare, but rare enough that its heart breaking to a lot of people to see them heavily modified. The truck wont do what you want it to do without basically swapping it all onto a new chassis, and again you're money ahead just selling it and buying parts.

The f100 will not take the F600 parts. Look at the chassis differences, wider, taller and thicker. If you want a 4x4 f100 there are easier and better end result solutions.

I'm the guy who has spent a stupid amount of time trying to get the same end result truck as you. Maybe you'll find a way that I didnt, but in the end I came to realize it just cant do certain things. So it will always have to be a certain way.

To get that dream requires a chassis swap and even then the 4x4 aspect of it just doesnt ever turn out right on these years. There is a reason you dont see them finished. It's an awesome idea on paper, but it doesnt translate in reality. The coolest that truck will be is stock and restored, any other mods to it will take away the MH cool one way or another.

I get the truck you want it to be, trust me, 10+ years chasing that dream man, but that is not the truck you want to use to get there. If nothing else you dont ever want to look back and regret destroying one dream for another.

 

Well put Steve.

There are guys out there that want a working big MH truck to restore as original. Maybe they will use it to haul a vintage tractor to a show.

Don't ruin a rare rare working truck. As Steve said buy a cab and front clip and put it on a modern chassis .... but that ain't easy to make it work and look right.

 

Another vote against the diesel swap. As stated, medium duty trucks from the 50s weren't designed for the torque of modern diesels. Spline counts on axles, gears, shafts, etc. do not compare with modern counterparts designed for higher torque loads.

 

I'm trying to learn about the possibilities. Specifically, I want to know if the internal components of the MH can be replaced or modified to allow highway driving speeds. If anyone with expertise can please provide input I would greatly appreciate it.

 

Thank you for your words. I trust what you say. I agree with the safety comments, drivability, and more. I guess that I have seen one too many episodes of Diesel Brothers and figured there is a way if I find the right shop and experts. But, yes, its going to remain a stock MH.

So much for purchasing 2 Dodge Ram 12 valve, Cummins. I literally bought 2 in the past few weeks. One was a 1st gen (pre intercooler model 1990), the other is a 1997 with NV-4500 standard trans. I decided to fix up the 1990 with new paint, etc and it will be sold ASAP. I bought it for $3,500 and should be able to sell for maybe $12,000 after the resto is complete. No loss there... More money for my projects. The other has a perfect, original powerplant so my plan is to keep it and use it to haul my F600 back from Oregon.

Since the motor will not go into the F600, I will find another use for it down the road. I only paid $2,400 for that truck. It runs well. Needs breaks, shocks and that is about it.

 

I am a little late to your party, plans change after 2 years, but that Cummins likely isn't too strong for most of those components, assuming you are not going to stomp on the pedal while it is in low 4x4. Honestly if you get an old manual cummins flywheel it may even have the same input shaft spline. the 1955 transmission had a 1-3/8 10 spline shaft and so did the 2500 dodge cummins of the 2000 era, of course you will likely need a new bellhousing.

 

I think you might be assuming too much.

 

About the parts fitting or power? If he just wants a diesel daily driver then the parts are plenty strong.

 

Hi, I just joined FTE and I have F600 MH 4x4. What has happened with this truck? You mentioned that the half shaft is out of the truck. Did you mean front drive shaft? If it is the front axle half shaft, why? I am in need of a left front half shaft, because mine broke. I hope someone sees this post and can help me.
Thanks in advance.

 

Welcome Truckfarm. Broken or missing half shafts are a part of the MH experience. Several of us have been there. One solution is to find yourself a parts truck (“can’t have just one!”). The other is to contact Chuck Mantiglia of Chuck’s Trucks to see if he has any. Also, Chuck now has available new sets of axle shafts. Stu

Chucks Trucks LLC., Chuck's Trucks, Chucks Trucks

 

Thanks Stu,
I am in pursuit. It looks to be fairly complex with the Bendix Weiss joint and end play shims with button on the inside end. My snow plow froze to the ground and I tried to rock it loose. Bang!!! Lesson learned the hard way. From now on if possible,it will be to tap it light. What a bummer.

 

You could start your own thread about axle shaft pursuit as well, Another option if you search around there are companies that will weld axle shafts back together as well!

 

I’ve known of guys who have had shafts welded, but it’s not always possible or successful. Below is one I had. Plus, Chuck has told us that even minimal end play when the knuckles are held in compression can itself be terminal. Especially on a truck such as yours that is still used for work. Stu

 

Does anybody know if this is a Marmon-Herrington conversion? Probably a fire truck at one time? It certainly is a nice looking truck.
https://www.facebook.com/photo?fbid=520294003436449&set=a.470389491760234

 

As now assembled it does not suggest MH origins. Locking hubs, right side front diff, eight lug wheels. All modern features. Whether it has some MH in there or not there’s no telling from the pics. Pretty sure 1934 is too early to have anything original MH going on. Stu