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Old 04-08-2018, 05:11 PM   #1
FriskyFleabag
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Cummins to sm465 in k10?

I have a 72 k10 that I really want to convert to a 12 valve Cummins. I have a 350 sm465/np205 in the truck now. I would like to keep the 4 speed as I don't really need overdrive due to 35's and 3.08 gears. Does anyone have links or maybe previous builds with more info going in a 4x4? Thanks
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Old 04-08-2018, 06:34 PM   #2
sweetk30
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Re: Cummins to sm465 in k10?

they did offer 4bt in gm p30 bread trucks and some were auto and some were stick . so there should be factory parts out there . this much i do know . sorry more of a gas guy . and i dont think that 12 bolt 1/2 ton axle will live long under the power of a 6bt engine . and the ball joints in the dana 44 front wont like it .

but others have done it so yes it can be done .
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Old 05-21-2018, 12:48 AM   #3
Peanutbutter
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Re: Cummins to sm465 in k10?

P 30 bread vans are getting a lot harder to find, used to be the best way to find a 4bt and flywheel bellhousing adapter. Even if you go with a 6bt the adapter plate and the flywheel are the key. One thing to remember is if the adapter plate is from a bread van it cants the motor 7 degrees, you either cant the motor or the trans but the motor and trans is out of sink 7 degrees. In my 1990 K 1500 the trans and transfer case is canted.
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Old 05-21-2018, 01:25 AM   #4
Stocker
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Re: Cummins to sm465 in k10?

A bit out of my element, but wouldn't the front end of a K10 need to be be strengthened to handle the extra weight of a Cummins? Stuff like springs, shocks, and front axle might need to be changed to something stouter. It'd be a snap for anyone who's up to the engine swap.
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Old 05-21-2018, 10:39 AM   #5
kwmech
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Re: Cummins to sm465 in k10?

Yes, the 12v engine comes in at almost 1300 lbs, whereas a 350 engine is about 550 lbs. The amount of torque with the 12v will destroy the 1/2 tons axles especially with the 465. So 1 ton axles are in order. 14 bolt rear and a 60 front. Matching gearing will be at a 3.73 ratio. So an overdrive trans is in order also
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Old 05-21-2018, 12:11 PM   #6
Peanutbutter
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Re: Cummins to sm465 in k10?

There are people swapping 4bs and 6bs into light chassi with no consideration to logic. Just because you can put them in there doesn't mean you should. As for the torque, I've seen two different 4BT bread trucks with 400 turbo trans that broke the converter housing right off the trans case. Don't under estimate the torque of the 4BT 6BT.
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Old 05-21-2018, 09:05 PM   #7
kwmech
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Re: Cummins to sm465 in k10?

Most people go after the cool factor before they think things out. The 6bt as it sits does not fit into the compartment of a 67-72 without cutting the firewall and a modification to the core support. Modifying the suspension with heavier springs. Boxing the frame helps A LOT. 1 Ton axles are just about mandatory. Gearing is a huge factor as the diesels are happy between 1800-2000 rpm. Of course nobody wants a stock 6bt, gotta turn that muther up with new nozzles and a modified pump. Why do you think Dodge finally went with a Dana 80 rear. All the Fords came with a Dana 60 front with the diesel option, as well as Dodge. Brakes!, cannot really use the vacuum booster anymore, hafta put in a hydro boost system if you really want it to stop.


Edit..forgot about the tires. Your 35'' tires may not make the grade depending on the side walls. All of the factory trucks require an 8 or 10 ply tire so the torque of the diesel doesn't shred the side walls. Years ago I had a tire store next to my old shop. They mistakenly installed a set of 6 plys on a Dodge diesel truck. 2weeks later they were changing them out under warranty for some 10 plys. I didn't get the whole story, but I understand the truck was pretty squirrely to drive when towing a trailer

Last edited by kwmech; 05-22-2018 at 11:23 AM.
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