Anyone else have a 67 K25 with 10000lb GVW?

[RedRoad]

Looking at all the options available at the time as mentioned the tires would be the hard thing to get to be rated at 10K. All of the chevy literature pretty much requires dually rear end. Was there any difference in the C&C axles vs K20? Wonder if the duals got swapped out at some time after the tank or pump beds were removed. The LW code does list C30 4.57 gears and all the lists show a C30 axle as 7200.

Clinton said his had all 4 9.75x16.5 wheels, I dont even see that as an option at least on the chevy literature.

If I was the engineer that got tasked with building a 10000lb GVW 4x4 with off the shelf parts at the factory I would do what appears they did.

High torque engine
HD Dana 44 front axle
Increased rate front and rear springs with rear overloads
Dually? or larger wheel tire option
Power Brakes
Power Steering? I thought most were removed early due to leaks
HD HO72 with optional 4.57 gears (surprised it wasnt 5.13s)
Locker?
HD 4 speed transmission w/drive shaft parking brake
HD radiator
HD front and rear shocks


other than tires the other weak link in the 67-68 trucks was the new tapered spring design. As you can tell the amount of leaves needed to bring up the rating was pretty extreme.

[Bob B.]

Good point about the tires. FWIW, RO5 dual rear wheels were only available on C-2500 cab and chassis, and roof marker lights were mandatory. All '67 K-2500's had Spicer 60 rear axles, C-2500 RO-5's and C-3500's used H-072 with H-110 optional (14,000 GVW) on long wheelbase cab and chassis. All this according to the GMC data and parts books. I think it's clear these trucks were some sort of specific COPO. An interesting combination of factory parts.

[factorystock]

Originally Posted by RedRoad

Ive never seen a factory longhorn 4x4 truck, didnt know they existed.

What made the 68-69 10K plate incorrect on those trucks?

No factory longhorn 4x4 that I aware of, was referring to the 2wd 1 ton longhorn. A 4 tire 1 ton does not have the capacity of a 6 tire 1 ton. GM stamped some '68-69 4 tire 1 tons with an incorrect 10K plate. So, there is no way a 3/4 ton model 2x4 or 4x4 would be rated at 10K. IMO, somebody goofed up during this period (like on the 1 ton longhorns) or the special order office tweaked the plate to get the sale.

[special-K]

What I find odd is why? At least here in Maryland, as I mentioned before, I can legally register any 1/2t or 3/4t "up to" 10,000# GVW just by checking a box and paying more for registration. 1t trucks can be registered "no lower than" 10,000# GVW. My '92 K3500 single rear was rated at 9200# GVW. We have special Chesapeake Bay plates that are only available for cars and trucks under 10,000# GVW, the line drawn between personal and commercial vehicle. I was not allowed to purchase these plates for my factory 9200# GVW truck because the VIN states it is a 1t. Go figure

[57taskforce]

Originally Posted by special-K

What I find odd is why? At least here in Maryland, as I mentioned before, I can legally register any 1/2t or 3/4t "up to" 10,000# GVW just by checking a box and paying more for registration. 1t trucks can be registered "no lower than" 10,000# GVW. My '92 K3500 single rear was rated at 9200# GVW. We have special Chesapeake Bay plates that are only available for cars and trucks under 10,000# GVW, the line drawn between personal and commercial vehicle. I was not allowed to purchase these plates for my factory 9200# GVW truck because the VIN states it is a 1t. Go figure

I know it’s similar or used to be anyway in Virginia, we always used to pay the extra and register at 10,000 to become Exempt from emissions testing. The downside like you said, is that you can only get truck tags if you go the route. Here in New Mexico it seems you can only register what is on the vin plaque.

[MJN]

Originally Posted by Ironangel

The Timpco has a Dana 60 knuckle front, the red truck has the later king pin Dana 60 front. Dana's axle charts for GM only go back to 77 and according to BillaVista.com GM never used the Dana 60 front with the closed knuckle design, only the spring loaded king pin type. So now I'm really confused! I think Tim is correct in that these were COPO one off ordered trucks. The GM and Dodge Dana 60 fronts were almost identical with the differences noted in BillaVista.com http://www.billavista.com/tech/Artic...nt_Axle_Bible/

Neither of these trucks has a Dana 60 front axle. They're both Dana 44.

[HO455]

It is possible that the 10K trucks came original with 17.5 or even the 19.5 wheels. There are 8 ply tires rated for 2450 lbs listed in the 67 literature. (R75b, R96a, R97a, R98a, R99a) These are shown as for dually use only by Chevrolet, they were not uncommon and be found on other brands from the 1950's forward into the early 70's on 4 tire trucks. I believe they were generally referred to as Hi-lift wheels. I have a set of Dodge 17.5's. In the non- split rim variety.

[MJN]

Originally Posted by HO455

It is possible that the 10K trucks came original with 17.5 or even the 19.5 wheels. There are 8 ply tires rated for 2450 lbs listed in the 67 literature. (R75b, R96a, R97a, R98a, R99a) These are shown as for dually use only by Chevrolet, they were not uncommon and be found on other brands from the 1950's forward into the early 70's on 4 tire trucks. I believe they were generally referred to as Hi-lift wheels. I have a set of Dodge 17.5's. In the non- split rim variety.

I know this is Chevy info but in the 1967 GM Info packet standard equipment K20 Cab/Chassis & C/30 cab/chassis wheels were 17.5x5.25". 19.5 x 5.25" and 16.5 x 8.25 were optional for tubeless type. 16x6 and 17x6 appear to be optional tube-type wheels.
https://www.gmheritagecenter.com/doc...olet-Truck.pdf

[Ironangel]

Originally Posted by MJN

Neither of these trucks has a Dana 60 front axle. They're both Dana 44.

, I'm not disputing that, but without getting into a pizzing contest, please tell me how you know they are 44's vs the 60's? I assumed they were 60's because of the 1 ton 10,000 pound ratings. Without looking at the casting number on the center section or the BOM number how can you visually tell one from the other? I mean without measuring u-joints or tube diameters? Again, i'm not saying your wrong, I'm asking you to explain to me why I am wrong...Were the axles noted on the SPID?...
Thanks! It's becoming more difficult to recall what I cant remember and then suddenly remembering what I never knew...

[Bob B.]

No Dana 60 front axles listed in any '67-'69 literature I have ever seen. The interesting thing about these 10,000# K-2500's is that every part in them appears to be an available standard or RPO component in either a K25 or C35. There were built right out of the GMC parts catalog.

[special-K]

The Dana60 front drive axles we are familiar with have only one u-bolt on the passenger side. The inner mounting holes on the spring plate get bolts threaded into the differential housing. Also size and proportion. The Dana60 cover is much bigger than a Dana44 and when you're used to looking at them it is obvious. Then there are the noticeably larger axle tubes.

Here are my finned 44 and 60 covers for comparison

[MJN]

Originally Posted by Ironangel

, I'm not disputing that, but without getting into a pizzing contest, please tell me how you know they are 44's vs the 60's? I assumed they were 60's because of the 1 ton 10,000 pound ratings. Without looking at the casting number on the center section or the BOM number how can you visually tell one from the other? I mean without measuring u-joints or tube diameters? Again, i'm not saying your wrong, I'm asking you to explain to me why I am wrong...Were the axles noted on the SPID?...
Thanks! It's becoming more difficult to recall what I cant remember and then suddenly remembering what I never knew...

Special-K stated the biggest visual difference with a 60 using one u-bolt and two cap screws on the passenger side. Also, in the red truck you can see the axle has ball joints and not king pins as a 60 uses, the kingpin will have a grease cap held on with 4 cap screws and a grease fitting in the center. The lockout hubs are also a Dana 44 giveaway.
I found this thread with some photos of a closed knuckle Dana 44 as well. http://67-72chevytrucks.com/vboard/s...d.php?t=661660

[67C10Step]

All I gotta say is I have come back a half dozen times to this thread just to look at the truck. It doesn't matter to me how it got to that configuration, I love that beast of a truck.

[Bayz68]

all righty...its been a LOOONNGGG time since I've posted anything... IF I have posted anything lol! The red truck is currently mine. I'm surprised no one recognized the brake caliper..or the steering dampener( the mounting bracket welded on the tube) The front axle is out of a 78. the original is in fantastic condition and is Just like RedRoad's Dana 44 small enclosed knuckle. I have NOTHING to go by on this truck ...not even the Title which states it as a 1976 or 78..have to look again, because that's when P.A. released it to the public. I can only go by what it has. The frame is untouched since the factory or ? because the frame, springs, axles where painted by the fire station in red(maybe i should have left it like that..regrets). All info from RedRoad is correct(LW code, wheels etc) project has been on hold since moving. and once i get the ceiling in the new barn, I should be able to start on her again. I want to keep it original. but nothing but the VIN would help that. soooo...crewcab? extended cab? I bought a stepside bed off a 69 firetruck I was planning on using. ..who knows...skys the limit.. opinions?(here we go!! lol)

Drivetrain plans are a draw through Turbo(1980pontiac setup) 401 gmc V6 (not v8) with the original SM420 to a NP208 if doable and a tailstock O.D. unit(new venture?). If i end up going factory, I may leave the turbo off.

I would say wheels are my kicker right now. I hear and see nothing good with 16.5 wheels. I don't like the mock up 16"s (16.5 x9.75 look-a-likes) ..they have the external bumps for the hub caps. This truck (supposedly) came with the 66 GMC hubcaps. Which i still have. Maybe stockton wheel can install my center section on 16's or 17s?? Happy to see all the attraction!!.

[Bayz68]

I now realize, RedRoad is sharing the gold truck. I thought it was his. My bad. Special-K, I suspect they physically and legally needed it for 10,000gvw due to being a water tanker...im guessing it was only a 1,000 gallon tank, I believe its 8lbs per gallon if memory serves me right. if it was, this girl was overloaded and then some. but all that is Speculating...

Front axle rated at 3300 and rear at 7200. 10500lbs. There is a factory 1ton 2wd 9ft(?) stepside that's red, all original. I think it has the 16.5x9.75 on the rears? maybe they just put them on all four corners for this kseries. ? maybe the gold trucks rears are correct and his fronts wrong...who really could tell us?? mine has hub caps. not like a fireman to go out and buy hubcaps (that just happen to be GMC 66, a rare cap from what i heard) for his work truck..maybe?

No power steering. Not sure if it had power brakes. came with a new booster tho..soo possibly!! It has a PTO that went to a brass water pump. No bed mounts (frame lumps?) no rear bumper, bolt on spring overload end plates made out of angle iron, just like the gold one.

wonder If I could fab some sulastic springs to cushion this Log wagon.
cheerios!

[Bayz68]

Originally Posted by factorystock

My take is, yes it was probably special ordered with a 10K plate for some unknown reason, but does not have the capacity of a 10K vehicle. IMO, it is no more heavy duty than a standard production 7600k 3/4 4x4. The conventional way of getting a 10k GVW 4x4 is the Napco conversion on a 1 ton with duals, which already has a thicker frame and larger brakes. A 1 ton 4 wheel longhorn had the GVW reduced to 8800 where only the 1 ton 6 wheel got the 10k. There were reports from GM that the factory stamped incorrect GVW plates for longhorn pickups at 10K on some '68-69's.

couple things to consider. it is a little more heavy duty than the standard 7600k. The rear end is the difference. Chevys had the 5200lb eaton and GMC had the dana 60 (5700? 6700?lbs cant remember). this girl has the 7200lb eaton. yes i know the only difference (HO52-HO72) is the spiders. 2 vr. 4. but thats a 2,000lb difference in strength.

Side note: LW code on the rear, as stated a few post above, means 7200lb eaton which mine is..but mine has no load bolt. so anyone who says the 7200lb eaton has to have the load bolt, well..hate to brake it to ya. SUPRISE!!!

this next one is speculation and memory. I remember reading somewhere, either hear or Facebook, someone had factory data on gm truck frames. There is a difference in physical strength in Tensile. comparing 1/2 and 3/4 tons and the 1 tons. It is Possible but highly doubtful, they could make two K2500 frames out of the C30 frames material. ..that would be cool. but I doubt it.

[factorystock]

Lively debate is always welcomed while we try to figure out what happened with these 10K GVW 4x4's. As I and others have mentioned earlier, GM had a problem with incorrect GVW plates on some models. Was aware of the C30 longhorn getting the C 30 dually plates, but never heard of the 4x4 plate issue. IMO, a dealership, probably the same dealership, special ordered some 4x4's with the 7200Lb rear axle to qualify for the 10K plate. This was kind of shady, if it doesn't have a thicker 5.05 section modulus 1 ton frame and bigger brakes.3/4 ton 4x4's came with 3.48 s.c. frames. While the math looks good ( 3300+7200=10,500) we don't see the GVW plates for a regular 3/4 ton pickups ( 3000+5200) for 8200LB, they were all 7500LB.

[Bayz68]

I wonder if that applied to 1967 as well? Lol our Trucks are the reason they quit doing it. Lol in 1970 that is. Bwhahaha, lol no. But in all seriousness , I do agree with what you said. And my Vin does too. KM2590 (3/4 ton).
... did/do? Fire truck builders(like timpco) follow the same rules as COPO or GM rules? I guess if you talk to the right person at GM, you can get anything? I can't think of a scenerio this would be called for , unless it was for a dirt road that went to remote location on top of a mountain and the only truck that can make it up would be a 4x4. And carry the maximum amount of water they can carry, Ive always heard single wheels grip better than duals!

So now what? Do I build her back to factory? Who would believe it if they saw it at a car show or in a parking lot? None right? I guess my main question is the wheels. Obviously 16.5s work as long as you keep the pressure up(60psi in the current ones) and I absolutely love the deep dish steelies. its a worry tho in the back of the mind..when will my tire pop off...But I also love very tall and skinny. Like 9.00x16 on 16x6.5 rims. (36in tall tires!!) But I heard those rims are rare as hens teeth...

[Bayz68]

I do want to clarify tho. I do not think GM stamping 10,000lb gvw was a mistake. Two completely identical trucks with overloads, same motor, trans, and most likely every option is probably the same. Both odd from all other trucks. There's a reason for the 10,000 ..we just haven't figured it out yet.

[factorystock]

'67-'68 was the height of wheel options on 3/4 ton GM pickups. A total of 5 wheel sizes, compare that to just 2 wheel sizes '69-'72. All these wheels have clips for hubcaps.

[Bayz68]

Do not read this post, it's a duplicate and I haven't figured out how to delete it yet.

I wonder if that applied to 1967 as well? Lol our Trucks are the reason they quit doing it. Lol in 1970 that is. Bwhahaha, lol no. But in all seriousness , I do agree with what you said. And my Vin does too. KM2590 (3/4 ton).
... did/do? Fire truck builders(like timpco) follow the same rules as COPO or GM rules? I guess if you talk to the right person at GM, you can get anything? I can't think of a scenerio this would be called for , unless it was for a dirt road that went to remote location on top of a mountain and the only truck that can make it up would be a 4x4. And carry the maximum amount of water they can carry, Ive always heard single wheels grip better than duals!

So now what? Do I build her back to factory? Who would believe it if they saw it at a car show or in a parking lot? None right? I guess my main question is the wheels. Obviously 16.5s work as long as you keep the pressure up(60psi in the current ones) and I absolutely love the deep dish steelies. its a worry tho in the back of the mind..when will my tire pop off...But I also love very tall and skinny. Like 9.00x16 on 16x6.5 rims. (36in tall tires!!) But I heard those rims are rare as hens teeth...

[Bayz68]

For kicks and giggles what wheel options for 66? Tallest tire wins, Lower those crazy rpms.

[special-K]

I have no idea what happened here. But what I know about 4wd trucks of this era is, if you needed a 1t 4wd (10,000# GVW), that was very possible. You would order a C/30 and have a NAPCO or Howe conversion done. These are two of the many equipment upgrades available through the dealership using the GM Silver Book. The truck would be sent out prior to delivery to an upfiitter, then delivered with the cost included on the invoice.

[factorystock]

Correct special k. A Napco conversion on a C 30 would have been the proper way to get the 10K plate and sure would have been much more expensive. IMO, some corners were cut to come in low on the bid price ( fire depts. on a budget?) The 1966 wheel options were the same as '67 and '68. Only difference is the 16.5" was a special order option in '66. A member has a '66 K 20 with 16.5's" on the SPID and has a special option code.

[Dieselwrencher]

Originally Posted by Ironangel

, I'm not disputing that, but without getting into a pizzing contest, please tell me how you know they are 44's vs the 60's? I assumed they were 60's because of the 1 ton 10,000 pound ratings. Without looking at the casting number on the center section or the BOM number how can you visually tell one from the other? I mean without measuring u-joints or tube diameters? Again, i'm not saying your wrong, I'm asking you to explain to me why I am wrong...Were the axles noted on the SPID?...
Thanks! It's becoming more difficult to recall what I cant remember and then suddenly remembering what I never knew...

Here's more food for thought. Chevy never used a D60F until 1978 in a K30. Plus, the axle of choice for a Napco, Howe, or even Marmon Herrington 4x4 conversion was an Eaton front. So, if these odd trucks were to have any other axle besides a D44 which was the only one they offered, I'd bet it to be an Eaton front. If it was the HO72 variant, you would have had your GVW handled too. Especially with 17.5 or larger rim size tires.