Bought a 440 and tranny from a 70's motorhome. 88,000 and it runs great!

Has anyone here put one of these bad boys into a D100? I have the 3.9 now.

Ideas? What might I run into?

 

when i replace my 3.9 with 5.2 i had to make a motor mount extension plate for the left side of the engine. i think you will also need to replace the radiator with a bigger one.

 

Yes I knew I'd be replacing the radiator and figured mounts. I know the tranny is different too so I grabbed the matching one. Not sure what model it is though.

Was the V6 rear axle weaker than the V8 one, or were they different?

 

You will need many parts. I put a 361 big block into a 73 D100 and it was not tremendously difficult. The radiator, front coils, motor mounts and transmission mounts are definite. Possibles depending on how the motorhome was laid out are oil pan and exhaust manifolds. It has been a while (1986) so this is all that I recall. Good Luck and have fun. You might want to upgrade the rear end as well.

 

Are there any bolt-in rear axle upgrades? Or would something beefier need to be custom?

 

Just put a rear end from a D250 and you will be set.

 

Find out which rear end you have first.
If it's the 8 3/4 or 9 1/4 you will be OK.

 

The 1/2 ton rear is most likely a Chrysler 9.25... nothing wrong with that but if you're planning on building the 440 up you'll want a Dana 60... should be stock for 3/4 and 1 tons and should be as easy of a swap as they get. (I'm currently swapping a 60 rear into my W100) Also, I'm not an expert but your transmission is probably a 727 (3 speed) or 518 (3spd + OD) to my knowledge those are the most common stock options. Good luck with your build!

 

The rear end swap should be fairly simple as there should be lots of choices at your local junkyard. I had the smaller 1/2 ton (8.75) at first but I was playing around and exploded the spider gears. I upgraded to the larger 1/2 ton (9.25) and had no problems after that, but I only had the 361 not a 440. The problem with going to the Dana 60 is most that you will find are the 8 lug and you will have to carry 2 spare tires. Dodge put the 440 and later the 400 in some 1/2 ton trucks but am not sure what rear end they used.

 

If I remember correctly, the Torque converters in a motor home are a higher stall speed than one out of a car. I think the bands are also heavier in the tranny.
Is it gonna be street/strip, both, or just a cruiser? ARe you gonna do any engine mods, maybe a cam/lifter change?


GOOD LUCK