K20 vs. K30 Difference

[barrymattern]

Hi All,

I'm newer to working on these trucks, and I'm just getting started on a project to turn my 1985 Chevy Scottsdale C10 automatic into a 4-wheel drive manual. I recently purchased a donor 1984 Chevy Scottsdale that was sold to me as a 3/4 ton K20, and the plan is to swap the '85 body onto the '84 frame. Included in the sale was an SM465 & NP205.

The other day someone who has worked on these trucks many many years almost immediately said it looks more like it's a 1-ton given how heavy duty the suspension is (their exact comment was that it looked like it was PUD, which I believe stands for Public Utility Dept). I also heard a passing comment related to the thickness of some things (didn't catch all they said as they were talking to someone else).

I have the VIN which states it's a 3/4 ton Canadian truck with a J code for the engine, which I believe is for a 6.2 diesel (engine, trans, and t-case were not included on the frame). I was also able to decode it as 8001-9001 lbs (Hydraulic only brakes), with a 2815 cargo weight rating listed in the glove box for "Truck Camper Loading Information". Based on the floor cutouts and higher center hump it looks like it was a 4-speed, and it has 8-lug wheels.

This is NOT the truck, but it does seem pretty similar: http://www.rustfreeclassics.com/Chevy4X4/84K30_SRW_RegCab_Scottsdale_White.htm

Without having the doors or other paperwork I don't have the exact build specs other than what was listed above. Taking all that into account with the pics attached here is anyone able to confirm that the frame with current suspension is indeed a 3/4 ton vs a 1 ton? Or would more exact measurements be needed? I can try to get any other info it it's needed or is more helpful.

I'm looking to learn as much as I can, and I appreciate anyone's time in taking a look at these!

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[nvrenuf]

The bare frame pics appear to be a 3/4 ton frame. The axles are definitely 3/4 ton w/ the rear being a light duty axle (14 bolt semi floater rear axle).

 

[Turbo4whl]

^^^ Exactly what John stated. K20, not K30.

 

[barrymattern]

Good to know, thank you both for confirming!

 

[SquareRoot]

Its a K20. I have an 85 K20 with K30 axles. K30's frames are taller and have 14FF/Dana 60 axles.

 

[85K304SPD]

10 bolt front axle and 9.5" semi float rear axle on a K20 vs. Dana 60 front axle and 14 bolt 10.5" FF rear axle on a K30. and the frame on a K30 is one inch taller.
You will learn alot by the time that you get done. Big project.

 

[barrymattern]

10 bolt front axle and 9.5" semi float rear axle on a K20 vs. Dana 60 front axle and 14 bolt 10.5" FF rear axle on a K30. and the frame on a K30 is one inch taller.
You will learn alot by the time that you get done. Big project.

Yeah, it's a big project that keeps getting bigger as we go, but thankfully I'm able to work on this with my dad who has been a mechanic/body-man for the last 50 yrs. If not for him and his knowledge this wouldn't even be possible. I love it though, it'll bring new life to the truck that has been in the family for the last 20+ years

 

[MyHeavyChevy]

Hi All,

I'm newer to working on these trucks, and I'm just getting started on a project to turn my 1985 Chevy Scottsdale C10 automatic into a 4-wheel drive manual. I recently purchased a donor 1984 Chevy Scottsdale that was sold to me as a 3/4 ton K20, and the plan is to swap the '85 body onto the '84 frame. Included in the sale was an SM465 & NP205.

The other day someone who has worked on these trucks many many years almost immediately said it looks more like it's a 1-ton given how heavy duty the suspension is (their exact comment was that it looked like it was PUD, which I believe stands for Public Utility Dept). I also heard a passing comment related to the thickness of some things (didn't catch all they said as they were talking to someone else).

I have the VIN which states it's a 3/4 ton Canadian truck with a J code for the engine, which I believe is for a 6.2 diesel (engine, trans, and t-case were not included on the frame). I was also able to decode it as 8001-9001 lbs (Hydraulic only brakes), with a 2815 cargo weight rating listed in the glove box for "Truck Camper Loading Information". Based on the floor cutouts and higher center hump it looks like it was a 4-speed, and it has 8-lug wheels.

This is NOT the truck, but it does seem pretty similar: http://www.rustfreeclassics.com/Chevy4X4/84K30_SRW_RegCab_Scottsdale_White.htm

Without having the doors or other paperwork I don't have the exact build specs other than what was listed above. Taking all that into account with the pics attached here is anyone able to confirm that the frame with current suspension is indeed a 3/4 ton vs a 1 ton? Or would more exact measurements be needed? I can try to get any other info it it's needed or is more helpful.

I'm looking to learn as much as I can, and I appreciate anyone's time in taking a look at these!

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[MyHeavyChevy]

What you likely purchased is a 3/4 ton heavy duty. It would have the big brakes and it is rated as 8600 GVW. I have an 85 3/4 heavy duty that is all stock except for a 3 in. Body lift I put on it. The door label shows it has the 8600 GVW rating too. What this means to you is much of the drivetrain is 1ton without the dually wheels.

 

[Strick]

What you likely purchased is a 3/4 ton heavy duty.

What is in the photos is LD 3/4 ton. 10 bolt front diff with 9.5 SF 14 bolt rear. The SM465/NP205 combo is fantastic and the brake calipers on the front have the larger piston along with larger brake shoes on the rear; but it definitely isn't a Dana 60 front and 14FF rear with 13" brakes. That's the HD stuff.

HS

 

[Blue Ox]

What is in the photos is LD 3/4 ton. 10 bolt front diff with 9.5 SF 14 bolt rear. The SM465/NP205 combo is fantastic and the brake calipers on the front have the larger piston along with larger brake shoes on the rear; but it definitely isn't a Dana 60 front and 14FF rear with 13" brakes. That's the HD stuff.

HS

Up to a point....

I own a 1985 3/4 ton and it was built with the C6P 8600 GVW package. So it was heavy duty emissions with a "J" code diesel engine with a 10" GM front and a 14 bolt semi floater rear with 13" drums and the heavier frame modulus that went with a heavy 3/4 ton truck as opposed to a "light" 3/4 ton.

There's a frame spec thread somewhere in the library that covers it.

There's a split in the 3/4 ton trucks from the 1973 to 1980 truck vs the '81 & up trucks where the components got lighter. A D60 front and 14 bolt full-float rear was 1 ton territory at that point.

 

[barrymattern]

Up to a point....

I own a 1985 3/4 ton and it was built with the C6P 8600 GVW package. So it was heavy duty emissions with a "J" code diesel engine with a 10" GM front and a 14 bolt semi floater rear with 13" drums and the heavier frame modulus that went with a heavy 3/4 ton truck as opposed to a "light" 3/4 ton.

There's a frame spec thread somewhere in the library that covers it.

There's a split in the 3/4 ton trucks from the 1973 to 1980 truck vs the '81 & up trucks where the components got lighter. A D60 front and 14 bolt full-float rear was 1 ton territory at that point.

@Blue Ox Thanks for sharing this info, very helpful. Looking at my VIN it looks like this truck is a "J" code diesel as well, along with a "G" code for brakes:
8001-9001 lbs (Hydraulic only brakes). Based on this and your info it sounds like it could be an HD K20?

 

[Blue Ox]

@Blue Ox Thanks for sharing this info, very helpful. Looking at my VIN it looks like this truck is a "J" code diesel as well, along with a "G" code for brakes:
8001-9001 lbs (Hydraulic only brakes). Based on this and your info it sounds like it could be an HD K20?

Probably. J engines were HD, which had to be over 8500 GVW for emissions. Look in the intake and see if there's an EGR valve. C engines had them, Js did not. All diesels has hydroboost brakes if that's what you mean by hydraulic.

 

[Strick]

Up to a point....

I own a 1985 3/4 ton and it was built with the C6P 8600 GVW package. So it was heavy duty emissions with a "J" code diesel engine with a 10" GM front and a 14 bolt semi floater rear with 13" drums and the heavier frame modulus that went with a heavy 3/4 ton truck as opposed to a "light" 3/4 ton.

There's a frame spec thread somewhere in the library that covers it.

There's a split in the 3/4 ton trucks from the 1973 to 1980 truck vs the '81 & up trucks where the components got lighter. A D60 front and 14 bolt full-float rear was 1 ton territory at that point.

I don't see any K30 pieces (frame, differentials) in the pics supplies in the post. Another poster had replied that it was the HD K20 and that is not is what is in the pics supplied. I have a '79 K20 now that is a 10 bolt front and 14FF rear and have never seen a K20 with a front Dana 60. Dodge, Ford, IHC and even Jeep do this on 3/4 tons but I've never seen one from the General. Ford even had a few F-150's with 5 lug Dana 60's on both ends. Here we go down the rabbit hole...

 

[SquareRoot]

What you likely purchased is a 3/4 ton heavy duty. It would have the big brakes and it is rated as 8600 GVW. I have an 85 3/4 heavy duty that is all stock except for a 3 in. Body lift I put on it. The door label shows it has the 8600 GVW rating too. What this means to you is much of the drivetrain is 1ton without the dually wheels.

How about a photo of that "Beautiful" 3 inch body lift?