I will be honest here. I LOVE the dodge motor, but I am not a big fan of the bodies. My wife and I want something a little different. I LOVE the look of the 67-72 Chevy trucks, but I want a differrent motor in it. I will use this truck as a tow rig (Towing rockcrawler), and an around town driver. I was thinking this:

Cummins 6BT from 1st gen cmmins truck BUILT
TH400 built to the gills (I want an auto)
NP205
Dana 44 front (Until I can swing the cost of a 60)
14 bolt in rear
4" lift
35's
All this wrapped in the body of a 67-72 Chevy shortbed.

Has anyone done a swap like this before? Would you recommend this, or am I getting in over my head? Would you rather throw in a 12 valve or a 24 valve?

Thanks
Dima

 

I don't think anybody has done that before, and I can think of a few potential pitfalls. I have a few suggestions:

1. Don't build up the th400. Leave it stock, it'll be cheaper that way when it breaks.

2. Start with a 1 ton truck of the type you want to build, then box the frame.

3. Ditch the idea of a 14 bolt axle. They weren't made to hold up to a built diesel, and were never installed in something with a strong diesel in it. Take a hint from that and act accordingly-a dana 80 will be cheaper once you account for the cost of fixing/replacing the 14 bolt a few times. Don't settle for a dana 70-they're about the same strength as the stronger of the two 14 bolt rearends.

In case you're wondering why I said what I said about the th400, it's not because I have anything against them. They're a fine transmission-for a drag car that makes relatively little torque (compared to a built cummins) at a relatively high rpm for a short time. You will most likely get to learn lots about what makes a 400 stop ticking if you put a 1000 ft/lbs or better built 5.9 cummins in front of one. Consider this: The power impulses transmitted to the transmission behind a cummins are much sharper than those transmitted to a transmission behind a v8, for three reasons. First, the cummins is just plain making more torque. Second, the cummins is a 6 cylinder instead of an 8 cylinder, so the tremendous torque it makes is packed into 3 torque spikes per revolution of crankshaft rotation instead of 4 like on a v8. This means that even if they made the same torque, the torque spikes produced by the cummins would still be higher. The trans/converter has to absorb this. Lastly, the cummins makes that high torque at MUCH MUCH lower rpms than does a gasoline v8. Guess what that means? Yep-even MORE distinct, violent torque spikes as the engine/converter rotates.

An EXCELLENT recipe to frustrate your trans builder to no end. There's a reason why built automatics that WILL handle that kind of torque cost $5000 or better. It ain't just because they have a 4th gear, either.

 

Awsome thought!!!

 

Don't waste your time with that one, a built Cummins and a 44 with a 4X4 launch at the drag strip or mud bog---Broken parts!

 

Never will it run at the DS (will build a Cobra for that)... I rockcrawl, so it wiill never see the mud at all. This will be driving around town, getting me up to Tahoe, and towing the rockcrawler to Moab.

I know I should get the 60, and I rpobvably will.

As for the TH400, I will probably end up going with a 4500 (But I really did not want the manual).

DIma

 

Ok, lemme rephrase part of what I said, and I think MC is saying:

If you build such a truck with a hopped up cummins, and through ANY use expect to actually use the torque capabilities of that engine, expect to twist a stock frame, break a th400, and as he said, probably also break a dana 44. If it's towing, it'll break the transmission. If it's rockcrawling, it'll break.

The key here is using the torque of the engine you propose to build-your drivetrain and frame in stock condition are not up to it. If you're gonna just putt putt around and not really use the power, then it may be ok. In that case, just put a stock motor in it and hope for the best. There is no way to weasel out of breaking stuff with a hopped up motor that's actually worked. You can not do this and not do that, but if you mess around and do something else that uses the torque, expect trouble.

I suspect you can beef up the frame enough if you start with a 3/4 or 1 ton and box it-that shouldn't be too much of a problem. Just reinforce the front suspension and steering to take almost double the designed weight (probably parts out there to do that) and put some weight in back so it won't be so front heavy, figure out the drivetrain, and you should be alright.

 

That'd be a sweet swap......but just like these guys have been saying, try to avoid using the TH400 or anything other than a Dodge tranny!! By the time you get done building a TH400 and fixing it everytime it breaks ( which it will ) just spend the money the first time around and buy a built Dodge tranny and be done with it. That'd be your best bet and it'll save you a TON of headache and a TON of money in the long run.



~Nick

 

I'm planning on a similar swap and the weight issue was my biggest concern. I love the concept of a diesel-powered SUV like the 7.3L Powerstroke Excretion but I can't get over the Ferd part of it.

So, what's the best-looking SUV of all time (to me, anyway)? The '68-'72 Chevy/GMC Suburban. I already have the donor powertrain--mine. The truck's nothing special to look at (Rocky Mountain pinstriping, coupla dings, faded paint, etc.) but the Cummins/NV 4500/Dana 60/Dana 80 powertrain will long outlive the body. It's all proven to work together and I just want to graft it all into the 'Burban frame. Might be hard to find a 3/4 or 1-ton '72 Suburban but I would think the frames were the same? Probably different springs, shocks and axles for 3/4 and 1-tons vs. 1/2 tons?

I'm considering multi-link, air-bagged front and rear suspension to hang the Dana axles from the Chevy frame. I've got to relocate the Dodge perches anyway. What do you think? Any links to suspension conversion companies or contact suggestions?

 

I doubt that the frames were the same. In my experience, the 3/4 and 1 ton frames are generally different/stronger than the frame of 1/2 ton versions of the same vehicle.

 

OK, here is what I can figure out... We are in the same boat when it comes to this swap. The frame CAN be boxed and made stronger. The stock frame is weak. So channl the hell out of it.

As for the suspension, redo the stock stuff under there. You can outboard the leafs if you have to. You can integrate some height into the hangers as well... I know I will be doing a shackle flip in the back, and some new springs up front.

Dima

 

V8440,
There is nothing wrong with a 14 bolt.They will hold up just fine.I have one in my truck and pull a #16,000 trailer all over the place with it.And the old truck isn't anywhere near stock, horsepower wise.
Keep the 14 bolt,there isn't anything wrong with them!

 

Well, as long as you use it for something that a dana 70 will survive, they're fine. I never felt like anything was WRONG with them, just that they aren't the strongest rearend out there. It's not at all inconceivable that the original starter of this thread may end up asking more than a 14 bolt can deliver.

 

I was thinking about the 14 bvolt thing... I think a 14 boilt is PLENTY strong. Hell my 99 CTD with 400hp at the rear wheels had a stock 60 back there... The 14 bolt is strong, but I agree that a 80 would be better. The rear end is the least of my worries... I am more worried about shoehorning the motor in there.

Dima

 

If you know how to weld, have an imagination and you aren't afraid of spending money you will be just fine!

 

Hey Flatty,where are you from?