6.2 to 350 swap

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RamblinGMC

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Has anyone gone from a 6.2 to a 350? What is involved in doing a swap like this? Weighing my options since the T400 blew and took the starter bolt mounts with it. Thanks for any advice!
 

RamblinGMC

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About to get underway with the swap. Are there any potential issues to watch out for? Or pretty much a straight up swap?
 

dvdswan

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I'm sure there are a lot of small things that need to be changed. Fuel system, engine mounting, transmission mounting, wiring, etc.

Engine and part of the cluster harness will be the big wiring parts.
 

Strick

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There's a big plug on the firewall that you can pull out with the wiring for the glow plugs and controller. I'd remove the filter housing from the firewall as well. The engine mounts should not need moving and just be ready for the small stuff like changing over the power steering pump, exhaust, radiator hoses, etc...
 

Blue Ox

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Chitty mileage?

I did the reverse swap, so I probably can't help. But I wish you luck.

The only suggestion I have to offer is to see if you can get a GM harness for the 350 instead of reworking the diesel harness. There's a lot more 350s going to the boneyard that harnesses can be scavenged from, and somewhere there's a diesel owner looking for a glowplug harness or a water in fuel indicator where you're probably eyeing a dumpster.

Just sayin'
 

Gilmore

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I did it recently, I changed fuel tanks, senders, motor and fuel pump obviously. The biggest thing I didn’t change that I should have was the fuel lines. I put in an inline filter and clogged three of them before I got it on the road. I also didn’t change my fuel tank change component inside the frame rails. If you have any specific questions let me know I’m happy to share as requested.

Btw… it was a full restore so also a painless harness.
 

Rickf

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Will your formally a 6.2 diesel need to pass a 1982 now 5.7 gas smog test?
 

Gilmore

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Not where I live no smog tests in rural NC.
 

Buck69

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Going to be starting a 5.7 install in the next couple weeks on a new to me '86 that was originally 6.2. Keep up with your posts. Sounds like we may be fumbling through it at the same time.
 

Gilmore

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Need pics?
 

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Strick

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It's not a terrible swap. When I built my '55 I started with a 6.2 & SM465/NP205. After driving a couple years it got where it would shut off. I replaced the injector pump with another and it did the same thing. So...I did a SBC swap and guess what? The same issue appeared. I had to vent the fuel tank lines (did the K5 rear tank swap) because it was locking the fuel line. I wish I had found the issue much sooner and then I'd still have the ole cornbinder clickety clack in my Twin Nickel.
 

Gilmore

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Yep I had this happen to my 84 when I installed the new tanks I didn’t install the vents I left them plugged and after running about 10 minutes it would starve out and shut off. When I opened the gas cap you would hear a huge vacuum.
 
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custodian

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I did in the 85 C10. Removed everything 6.2, I cut out what wires that were not needed, used a few for power sources. I even removed the Hydroboost and replaced it with power vacuum brakes.

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RamblinGMC

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I did it recently, I changed fuel tanks, senders, motor and fuel pump obviously. The biggest thing I didn’t change that I should have was the fuel lines. I put in an inline filter and clogged three of them before I got it on the road. I also didn’t change my fuel tank change component inside the frame rails. If you have any specific questions let me know I’m happy to share as requested.

Btw… it was a full restore so also a painless harness.
Curious why you swapped tanks instead of just cleaning and using the ones you had?
 

RamblinGMC

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Joined
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Clovis Ca
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Eddie
Truck Year
1982
Truck Model
c2500
Engine Size
6.2
It's not a terrible swap. When I built my '55 I started with a 6.2 & SM465/NP205. After driving a couple years it got where it would shut off. I replaced the injector pump with another and it did the same thing. So...I did a SBC swap and guess what? The same issue appeared. I had to vent the fuel tank lines (did the K5 rear tank swap) because it was locking the fuel line. I wish I had found the issue much sooner and then I'd still have the ole cornbinder clickety clack in my Twin Nickel.
Fill me in on the K5 tank swap? Sounds intereting.
 

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