What Trans for a cummins swap c10?

[cooper_joe]

I have a 1985 gmc c10 2wd 350 auto. I have a 12 valve that I plan to swap into it. I want a manual trans but i am not sure what to go with or what has already been done and documented (I have tried to do some research). I dont want a nv5600, i am leaning towards a nv4500 or a g56. I know for fords people use the zf5s and zf6s alot but not sure if thats the best option. The motor as is makes 300 hp but i plan for up to 500 and i dont plan to tow. This build is more of a fast street truck. I am looking for most budget friendly option, like using a dodge trans to save money on adapter plates, but if something is just that much better I would consider. Not sure if this is the best forum to post to for this info, appreciate all input.

 

[PrairieDrifter]

Why the double post? This isn't a Cummins forum and not many regulars that have done it.

I have started a Cummins swap, from what little knowledge I've got, for you a g56 would be the best option in my opinion. I've driven a couple, I'd say they're less mechanical feeling than other older transmissions. Can shift faster most likely, smoother shifts. Probably better for your needs.

I can't help with power ratings, but the dually I drove for work was about 500-600 hp with a g56, as far as I know. We towed heavy with it.

 

[TotalyHucked]

Man, I would not want to drive one of these squarebody half tons with that heavy ass lump of a cummins up front. I'd at least be putting it in a C6P 2500 or something

 

[squaredeal91]

I have a cummins truck and I couldn't afford an nv4500 so I ended up with the ZF5 speed and it works very well With my setup. Also you need to think about all the extra pounds. Its going to kill your wheel bearings. The engine alone weighs close to 1200#s lol. Im pretty sure the front suspension assemblys are interchangeable, you could change out to 3/4 or 1 ton.

 

[vr1967]

To put a Cummins in a C10, I’d change the front springs 82-87 C30 1 ton diesel springs.

For mounts, I’d build them using 3rd gen truck mounts. They make adapters for the gm frame mounts, but they wont last.

It will all go under the hood with some work. Looking to see if I have pictures of where we did the same to a buddy’s c10 a few years ago.

If you want to run a mechanical fan on a second gen (p-pump) 12v, use a 1st gen hub. It will give you an extra inch of room.

Have done a few Cummins into Chevys conversions since the 90s so may can give you some ideas.

 

[goldpack]

I think I would start by selling the C10 350 gas one to someone that wants it as is.
(you don't even have a heavy duty frame there).

then look at buying a one ton gmc/ chevy diesel truck, and swapping a cummins in to that.
(or start liking dodge bodies and make it whole lot easier.)

the thing that is not factored into budgets: your time / your sanity/ and how long such things take....and learning all the crap...and struggling with parts,...makes young men loose hair,...and gives middle aged men heart problems. ...in addition to a empty wallet for something that may not turn out, and be just a pile of used parts.

 

[Grit dog]

Another new member getting dissed by the vets…
Why the shade, @PrairieDrifter and @goldpack?
And who wants to make a C30 into a fast street truck? Although it would be nicer to have the stouter an arms and frame of a 3/4 or 1 ton, I don’t see much issue with the half ton save for springs which are easy.
@cooper_joe, while a manual would be cool, if I was thinking what you said you’re building….fast, street….presumably cruising and cruises, I’d make life easy now and easy driving and faster and just drop a 47 or 48re in with it. You get overdrive. You can build them to the moon as economically or more than any other plausible auto. It won’t cost you more than buying a G56 or similar and clutch etc.
Less work on install. Way less. Or less ingenuity rejected anyways.
And you’ll be able to heel toe burn outs and launches or cruise the strip with one hand on a beer and the other between your girls legs who couldn’t sit next to you if you had a stick shift….
Just my 2c on it.
And fwiw, I’d love to swap a 12v or 24v into our K20!
Hopefully you’re doing this and will post your progress.

 

[TotalyHucked]

cruise the strip with one hand on a beer and the other between your girls legs who couldn’t sit next to you if you had a stick shift….

Having a girl in the middle with a stick is always a good time lol

 

[DoubleDingo]

Having a girl in the middle with a stick is always a good time lol

Yep, Having a stick shift vehicle with a bench seat never stopped any females from sitting next to me. And yep, fun times.

 

[Terlingueno]

Yep, Having a stick shift vehicle with a bench seat never stopped any females from sitting next to me. And yep, fun times.

Reason #756 why I like my bench seat and 4 speed manual in my Suburban...

 

[idahovette]

^^^^^^^^^^WHY is that so far DOWN on your list^^^^^^^^^^^

 

[Terlingueno]

^^^^^^^^^^WHY is that so far DOWN on your list^^^^^^^^^^^

The difference between #1 and #756 is so tiny that is almost immeasurable...

 

[PrairieDrifter]

Another new member getting dissed by the vets…
Why the shade, @PrairieDrifter and @goldpack?
And who wants to make a C30 into a fast street truck? Although it would be nicer to have the stouter an arms and frame of a 3/4 or 1 ton, I don’t see much issue with the half ton save for springs which are easy.
@cooper_joe, while a manual would be cool, if I was thinking what you said you’re building….fast, street….presumably cruising and cruises, I’d make life easy now and easy driving and faster and just drop a 47 or 48re in with it. You get overdrive. You can build them to the moon as economically or more than any other plausible auto. It won’t cost you more than buying a G56 or similar and clutch etc.
Less work on install. Way less. Or less ingenuity rejected anyways.
And you’ll be able to heel toe burn outs and launches or cruise the strip with one hand on a beer and the other between your girls legs who couldn’t sit next to you if you had a stick shift….
Just my 2c on it.
And fwiw, I’d love to swap a 12v or 24v into our K20!
Hopefully you’re doing this and will post your progress.

Shade? Brother, I simply stated facts.

I assume he double posted because he didn't get a reply on his exactly identical first post. My second statement was the answer for my first statement.

Posting the exact same post multiple times isn't going to change the outcome, so why do it? My answer was that this in fact is not a Cummins forum so there aren't many regular members to help. Another fact.

THEN I proceeded to give him the best advice I've got at this point time.

How dare I?!?!? Right?? Never had a problem with you really, but you seem to be the common denominator in these **** posts lately...have to voice your opinion in the matter anyways some would say you're throwing the shade in this instance.

Now these useless extra comments clog up another newbies post.

 

[CheemsK1500]

A 12 valve isn’t the hardest swap you can do, though since you’re starting with a 1/2 ton, you will definitely want to beef up your frame and suspension. Granted, many 1/2 tons came from the factory with the 6.2 Detroit diesel, which isn’t exactly a lightweight engine, so the marginally heavier Cummins probably won’t be too punishing, but I’d still recommend some sort of reinforcements.

As for the transmission, the NV4500 is a solid choice, though it’s not native to square body, so you’ll have to fab up things like the entirety of the hydraulic clutch assist system.

Another thing to consider is that your truck has some vacuum controlled components on such as the HVAC system, brake booster and cruise control (if equipped.) for the brake booster, you can do a hydroboost conversion, for everything else you’ll need to rig up a vacuum pump and run the lines accordingly.

 

[PrairieDrifter]

A 12 valve isn’t the hardest swap you can do, though since you’re starting with a 1/2 ton, you will definitely want to beef up your frame and suspension. Granted, many 1/2 tons came from the factory with the 6.2 Detroit diesel, which isn’t exactly a lightweight engine, so the marginally heavier Cummins probably won’t be too punishing, but I’d still recommend some sort of reinforcements.

As for the transmission, the NV4500 is a solid choice, though it’s not native to square body, so you’ll have to fab up things like the entirety of the hydraulic clutch assist system.

Another thing to consider is that your truck has some vacuum controlled components on such as the HVAC system, brake booster and cruise control (if equipped.) for the brake booster, you can do a hydroboost conversion, for everything else you’ll need to rig up a vacuum pump and run the lines accordingly.

Vacuum pumps are pretty standard stuff since newer stuff and stuff of that era don't use cables. But that is a very overlooked/not thought about problem when doing a diesel swap. Good point to bring up.