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Discussion Starter #1
Picking up a SBC manual adapter kit and 96 Chevy nv4500

I want to put it behind my p-pump 6BT
is this a reasonable idea?
I am mostly concerned about clutch strength.
I want to turn up the 6bt a bit, timing bump, gov spring, ad some fueling, the cheap stuff.

clutch options?

I am not really interested in swapping to the dodge stuff
Thanks
Ken
 

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What size clutch disk does the Chevy flywheel accept? When I went from the 200HP level to closer to the 300 level on my 4BT the 11" disk in the Ford adapter was totally out matched, I talked to South Bend and they said that there was no 11" clutch that was designed to work in a working truck capable of holding that level of power.
I ended up going from the Windsor pattern ZF to the diesel ZF that adapter used the Dodge flywheel and it's 13" clutch IIRC that clutch from South Bend is rated at near 750 Ft/Lbs.
Once you know what size disk you can fit to your flywheel I would contact South Bend or one of their dealers and see what your reliable power level will be.........$.02
 

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Eggman is correct. The GM 4bt setup only uses an 11" clutch also. If your power level on the 6bt is staying around 200 HP you may be OK. Get much above that and it gets iffy real quick. The nemesis is the gosh awful torque the Cummins produces and once you get past a certain power level the 11" just can't hold it. Stock clutch on a 160 HP 6bt was 12.25" and when they went to the 24 valve they upped it to13" due to the higher power level.
 

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Discussion Starter #4 (Edited)
Ram makes a dual disc 10.5” SBC clutch setup. Curious if I can get that to work.

Looks like I may just be able to space the PP out like the flywheel provided.
Wonder if it would fit /work with the nv4500



 

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Ram makes a dual disc 10.5” SBC clutch setup. Curious if I can get that to work.

Looks like I may just be able to space the PP out like the flywheel provided.
Wonder if it would fit /work with the nv4500



I would contact their tech support to make sure it is suitable for service in a truck that will be used as a truck, no matter the initial cost doing it right the first time is always the most cost efficient route.
 

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Standard clutch for a 96 NV4500 GM is 12".

That will handle a pretty decent 12 valve fine. 12" organic should handle around 600 lb/ft if your nice with the pedal. Get side-steppy with it and you need ceramic and a tranny with a bigger input shaft.
 

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His GM adapter wont fit a 12" clutch
 

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Don't know if you noticed but that RAM kit includes a flywheel which you wouldn't need. The clutch/pressure plate assembly comes in 2 versions that run $800-1100 depending on power handling capacity. RAM does not mention how much torque they will handle, only HP. If you have the 2nd version GM NV4500 it would be better to change the input shaft and bellhousing to a Dodge Cummins type and use a Dodge NV4500 block adapter and flywheel. If you have the early GM NV4500 then you're sort of stuck because it has different bolt patterns.
 

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Discussion Starter #11
Char, yes I saw it come with the flywheel.

i can remachine the cummins sbc flywheel ad the same spacers as the RAM flywheel has.

I do not want to swap to dodge stuff. I have all the sbc items.
I know it doesn’t specify torque, I was planning on calling RAM and talking to a tech.
Transmission is a 1996.
The only possibility to swap to dodge is if someone had a good dodge nv4500 along with all the adapter etc and wanted to trade everything straight over. The dodge nv4500 would allow me to use the T-case I have where I am still trying to find a suitable candidate t-case for the Chevy nv4500.

A strong 32 spline driver drop t-case has very few options.

the stoutest/cheapest option I can think of is swapping a th400 32 spline input into a married Ford np205. I have the ford t-case already.

the easiest /most expensive would be buying an Atlas or STAK.

This all depends on how far I want to run down the rabbit hole!

or I give up on a 5 speed swap right Now and go back to my original plan and install the rebuilt 47rh/np273 I have sitting on the floor.
 

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I really don't follow what you guys are making a fuss about.

The GM NV4500 has a 1-1/8" input shaft and it will handle whatever the stock 12" GM clutch will give it.

They are a perfect match.

Again, why does anyone think the 12" GM pressure plate won't fit the 4BT GM flywheel? Has anyone involved in this discussion ever touched one? I have.
 

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Discussion Starter #13
I am going to hold off and see what shows up and how to proceed. I may be getting ahead of my self here
 

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If the pressure plate for the 12" clutch will bolt to the Cummins GM flywheel I'd assume it would fit. Don't remember anyone on the forum trying that as the standard clutch on the 4bt GM was 11". That 12" would get you to near the holding power of the base 6bt which I believe was 12-1/4". There are 12" GM dual plate models out there too.
 

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Discussion Starter #15
I found reference to people using a 12” clutch with the sbc cummins adapter when searching thru the forum. Hoping that is the case.
 

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You guys need to get out more LOL.

Look up LUK 04089 That's the 11" GM clutch.

Look up LUK 04902 That's the 12" clutch.

Both fit virtually every single GM pickup flywheel made from 4.3 S10 through 454 K3500 because they both have the same 12.625" pressure plate bolt spacing that GM has used since forever.
 

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Thought the ford and chevys used the same dia flywheel. Sorry, only know ford stuff.
 

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Thought the ford and chevys used the same dia flywheel. Sorry, only know ford stuff.
Somewhere in the back of my mind i recall discussions about one of the flywheels having two different pressure plate bolt circles, now I wonder if it was the Chevy adapter that had it.............or maybe I'm just way out in left field, I do have priors for being there :cool:
 

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Thought the ford and chevys used the same dia flywheel. Sorry, only know ford stuff.
In reference to the step van applications:

Outside diameters were the same.
Starter ring gears were the same.
Inside diameters were different due to the different pilot bearings that were used.
Thickness was different which also means the flywheel weights were different with the Ford application being lighter. As a side note, I have had a SM465 application flywheel that had been resurfaced enough time that the thickness was getting close to the Ford Borg Warner thickness.

Can you install the GM set up behind the 6BT? Yes.
What was the most common failure in using the GM setup? It was the nasty habit of clutch disk failure that was generally believed to have been caused by the low RPM & high torque of the Cummins engine. It seems that the clutch disk can develop a nasty problem of spitting out springs from the disk.

The SM465 application used a standard 12" diameter clutch disk that was carried forward from the original 6 cylinder step van application.

The Ford Borg Warner transmission applications used the standard 11" also carried forward from the original step van application.

Most originally used the OEM clutch pressure plate; Ford & GM that came with their respective 6 cylinder engines. In later years there were some dual pattern clutch pressure plates that would bolt to both the Ford (3 pairs pattern holes) and the GM (6 equally spaced holes).

Can you use the GM flywheel & clutch set up behind a 6BT? Yes, it has been done but the majority of past experiences that have been reported are somewhat dismal. Can you use a dual disk clutch? Yes if there is enough room to clear the inside of the bellhousing.

And most of this post has been coverd over the years in the stickys.
 
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