24v Cummins to th400 86K20 build

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snowwhite24v

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So I’ve decided to Cummins swap my 86 dually. I don’t really have a lot of mechanic experience other than driving old junk pickups all my life, pretty much teaching myself. I’ve had the 86 for ab 5 years now but i recently bought a 2nd gen Cummins and fell in love with it. I plan on buying an adapter to bolt the 02 Cummins engine I just bought to the th 400 that’s in the truck now. I am also converting the engine to a p-pump. The motor had a blown headgasket. I’m waiting on the injector pump and head gasket/studs in the mail. Any advice helps!! Thanks in advance
 

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Vbb199

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I looked into this for a k5 I had.

You'll need to maybe beat on the firewall some or cut it to fit the Cummins + radiator I do believe. Not by much? But it'll be a tight squeeze.

You'll need motor mounts to retrofit it in the engine bay as well.

Advance adapters sells a GM th400 to 24v adapter.

But also, earlier v8( around the 70's I think) Chrysler products had a th400 behind their 360, etc.

Something to ponder on.

I think the passenger side motor accessories may interfere with the frame rail also, as I understood from reading on the interwebz, so some clearancing may be needed


That's some information I remember reading, if it helps at all
 

snowwhite24v

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You mean this adapter? I bought a brand new one this weekend. As for the clearance issue. But really the only thing on that side is the exhaust manifold turbo and down pipe. And if it’s the down pipe it’ll soon be out the fender pipe. Thank you for the feedback
 

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Vbb199

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You mean this adapter? I bought a brand new one this weekend. As for the clearance issue. But really the only thing on that side is the exhaust manifold turbo and down pipe. And if it’s the down pipe it’ll soon be out the fender pipe. Thank you for the feedback


I understood you'd have clearance issues with accessories at the frame rail or something. Up front.

Maybe thats only specific to the 5.9 24v I wanted to install in my k5.

I dunno alot about these engines.

But yea. That adapter looks nice!
 

Corvette Ed

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Looks like Vbb199 pretty much got your questions covered. Sooo... Welcome to the forum from East Tennessee.
 

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