250 to 350 swap

[Wesley Coburn]

I have a 1977 k10 4x4. It is 250 6 cylinder 4 speed. But I have a 350 that I'd like to swap it out with.. what all will I need and how complicated of a swap is this?

 

[1987 GMC Jimmy]

Here's this with some info on motor mount brackets and PNs.

http://www.gmsquarebody.com/threads/82-c10-250-six-to-350-v-8-swap.9956/

Also, what does the motor have already? Is it 100% complete and ready to drop in? You'll need a V8 exhaust Y pipe if you're running factory exhaust for sure. I'm not sure about cooling hoses and fuel/PS lines. I'm thinking some or most will work, but it's not a serious swap by any means. Is there something wrong with the 250, or are you just tired of it? I really want a clean '54 Chevy 3100 roller that I can drop a 250 or a 292 in it, but I haven't gotten there yet.

 

[Wesley Coburn]

The 250 in it is fine. Truck runs and drives great. The 350 is complete. It's ready to run

 

[bucket]

6 banger 4x4's don't come along too often anymore. They are a bit of a rare breed.

I think it's neat.

 

[Wesley Coburn]

I agree. But I don' think the 250 Will do what I'm needing out of the truck. Anybody out there use there's to haul cars?

 

[bucket]

Cars as in, car'S' or just one car after another?

It's all in the gearing. They can haul about anything and put up with it, they just won't do it quickly.

 

[4WDKC]

I agree. But I don' think the 250 Will do what I'm needing out of the truck. Anybody out there use there's to haul cars?

werent there 3/4 and 1 ton offered with the I6?

 

[bucket]

werent there 3/4 and 1 ton offered with the I6?

Yes. Don't know about the 250 though. The 292 for sure was stuck between the fenders of bunches of them.

 

[Biggin0822]

My nephew has a 70s either 3/4 or 1 ton with a 292 in it. I think its got only about 80k original miles on it. Flatbed stake side. It was sitting in a clients barn for 20 years and we rescued it. this pic is just after we got it started for the first time.

You must be registered for see images attach

 

[tahitiansoul]

I had a 250 also and replaced with a 350, it is straight forward. Steering pump has same hoses, all you need is correct engine mounts, AC compressor lines, V8 radiator, radiator fan with funnel and you should be good to go

 

[MikeB]

The frame brackets for 250 6cyl and small block should be the same, at least they were on my 82 C10. However you will have to mount them farther apart and higher using factory-punched holes on the frame.

I have a pair of the 4WD clam shells on the shelf that are 11/16" shorter than the 2WD versions. I know they work for 81-up K trucks, but not sure about your 77. GM part number for both is 471634. They are sandblasted and painted.