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Dad's 1978 Chevy K30 Farm Truck

Dad's K30
Condolences on your Dads passing - I lost mine in 2019.

And I think it’s great that you are giving the ole family truck a bunch of love - hope it provides great memories for ya.

I do have a question or a comment on some parts on your truck,
A friend of mine and me ended up with a 1978 K/30 Cab Chassis Wrecker from a shop we worked with years ago - this shop bought the truck new and never modified it but it had a few things on it that always puzzled us and through your pictures I see that your Cab Chassis has the same puzzling parts.

Both trucks are 78 Cab Chassis’ and are part time 205 with the SM-465 but have full time slugs in the front hubs ( did y’all change those out ? ) but here is the really odd part.
On the rear spring hangers they are 2WD versions ( they don’t extend past the frame as much as K/30 ones do and therefore shorter than normal K/30 versions ) and to make up the height difference there is a short block in the back that this era trucks normally did not use.
Also on the K/30 wrecker it had a 4WD shifter knob that was for a 203 ( it was a normal 205 shifter but just came with a full time knob ). Also, the truck came with a front Spicer style cv-joint front shaft instead of the Saginaw style that was phased in GM trucks a year or two earlier. Just curious if your truck is the same ?
It’s good to see another 78 K/30 Cab Chassis that has the same components - I don’t bring these oddities up to too many folks because it’s hard to prove that these things were factory correct.

Could you post up more pics of these parts and the SPID sheet if possible ? Thanks
 
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Condolences on your Dads passing - I lost mine in 2019.

And I think it’s great that you are giving the ole family truck a bunch of love - hope it provides great memories for ya.

I do have a question or a comment on some parts on your truck,
A friend of mine and me ended up with a 1978 K/30 Cab Chassis Wrecker from a shop we worked with years ago - this shop bought the truck new and never modified it but it had a few things on it that always puzzled us and through your pictures I see that your Cab Chassis has the same puzzling parts.

Both trucks are 78 Cab Chassis’ and are part time 205 with the SM-465 but have full time slugs in the front hubs ( did y’all change those out ? ) but here is the really odd part.
On the rear spring hangers they are 2WD versions ( they don’t extend past the frame as much as K/30 ones do and therefore shorter than normal K/30 versions ) and to make up the height difference there is a short block in the back that this era trucks normally did not use.
Also on the K/30 wrecker it had a 4WD shifter knob that was for a 203 ( it was a normal 205 shifter but just came with a full time knob ). Also, the truck came with a front Spicer style cv-joint front shaft instead of the Saginaw style that was phased in GM trucks a year or two earlier. Just curious if your truck is the same ?
It’s good to see another 78 K/30 Cab Chassis that has the same components - I don’t bring these oddities up to too many folks because it’s hard to prove that these things were factory correct.

Could you post up more pics of these parts and the SPID sheet if possible ? Thanks

Free wheeling hubs were optional in the 70's. If you did not spring for the extra cost option, you got drive slugs, even though you had a part time case.

Martin
 
I was incorrect. By ‘78, free wheeling hubs were standard. They just were not available for a K30 yet. Interesting. I learned something new today.

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Close up.

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Here you can see that they were optional in '73.

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Optional in '75, but only on a K20 six cylinder. Because in '75, the only K series truck you cold get with a six cylinder was a K20 pickup. All '75 Blazer, Jimmy, Suburban, and K10 pickups had a V8 engine in '75. The NP203 was standard with a V8 engine in a 4x4 in '74-'75. Although I have seen several '75 model pickups with a V8 engine and an NP205. They have an RPO (MV1) for Conventional 4 Wheel Drive.

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'75 Information.

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Close up.

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Here is a '74 SPID for a K20 with MV1 Conventional 4 Wheel Drive and F76 Front Free Wheeling Hubs.

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Sorry for the high jack! Hopefully it was useful information.

Martin
 
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I was incorrect. By ‘78, free wheeling hubs were standard. They just were not available for a K30 yet. Interesting. I learned something new today.

View attachment 453989

Close up.

View attachment 453990

Here you can see that they were optional in '73.

View attachment 453993

Optional in '75, but only on a K20 six cylinder. Because in '75, the only K series truck you cold get with a six cylinder was a K20 pickup. All '75 Blazer, Jimmy, Suburban, and K10 pickups had a V8 engine in '75. The NP203 was standard with a V8 engine in a 4x4 in '74-'75. Although I have seen several '75 model pickups with a V8 engine and an NP205. They have an RPO (MV1) for Conventional 4 Wheel Drive.

View attachment 453994

'75 Information.

View attachment 453997

Close up.

View attachment 453998

Here is a '74 SPID for a K20 with MV1 Conventional 4 Wheel Drive and F76 Front Free Wheeling Hubs.

View attachment 453999

Sorry for the high jack! Hopefully it was useful information.

Martin
Damn good info !
I wish that I would have kept a log of all the SPID sheets on every K series truck that I’ve run across over the years…

I remember seeing literature about optional manual locking hubs over the years but just thought it was sales talk to make it sound better - I never realized that the manual hubs were optional on early part time squares; good to know.

Early K-30’s not having manual hubs makes some sense; I have never run across a 77/78 K-30 with manual Spicer hubs and a 205 case.
That would make Spicer D60 internal hubs a very short OEM run cycle from 79~81 on GM’s and only 79 on Ford F-350’s. Never realized that….
 
Man, if there was ever a statement that really made you want to stock pile, that's it! :eek:
We should have bought more Spicer stuff back when we had inside connections….
We should have spent more on cool parts and less on things like food, clothing and rent… our priorities were just not right when we were in our twenties !
 
On the spring hangers, 78 K30s used the 2wd version with a block in the rear from the factory. They did not have frames with the taller 4x4 hangers available for production yet.
Good to know !
I guess all the other K-30’s that I have seen in person have been 79+ with the taller hangers and was just baffled by the short ones on the 78 K-30 stuff.
Good info coming out of this thread!
 
Dang Kenny, I just saw this. Sorry for the loss of your Dad...
 
Why do rust free cabs, have the most stubborn cab mount bolts to remove? This thing doesn't look like it has ever seen road salt in its life but the cab mount bolts requires using a 1/2" breaker bar half of the way out. Impact guns are useless and more likely to spin the capture nut anyway. But I now have a donor floor and frame to start repairing my dad's truck with and I won't need to use the white C30 most likely.

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I was incorrect. By ‘78, free wheeling hubs were standard. They just were not available for a K30 yet. Interesting. I learned something new today.

View attachment 453989

Close up.

View attachment 453990

Here you can see that they were optional in '73.

View attachment 453993

Optional in '75, but only on a K20 six cylinder. Because in '75, the only K series truck you cold get with a six cylinder was a K20 pickup. All '75 Blazer, Jimmy, Suburban, and K10 pickups had a V8 engine in '75. The NP203 was standard with a V8 engine in a 4x4 in '74-'75. Although I have seen several '75 model pickups with a V8 engine and an NP205. They have an RPO (MV1) for Conventional 4 Wheel Drive.

View attachment 453994

'75 Information.

View attachment 453997

Close up.

View attachment 453998

Here is a '74 SPID for a K20 with MV1 Conventional 4 Wheel Drive and F76 Front Free Wheeling Hubs.

View attachment 453999

Sorry for the high jack! Hopefully it was useful information.

Martin
From the literature I had, 74 had np203 for all, but 75, 203 was with the automatic and 205 was on the manual.
I did have a 75 k5 sm465/205 .
 
From the literature I had, 74 had np203 for all, but 75, 203 was with the automatic and 205 was on the manual.
I did have a 75 k5 sm465/205 .

Your literature is wrong. There are '75 models with SM465/NP205's, but they have an RPO on the SPID for Conventional Four Wheel Drive.

Martin
 
Your literature is wrong. There are '75 models with SM465/NP205's, but they have an RPO on the SPID for Conventional Four Wheel Drive.

Martin
I owned it and had the literature from the dealership.
If your literature says different it could be a market thing, I was in the middle east. Different market could have a different option
 
Your literature is wrong. There are '75 models with SM465/NP205's, but they have an RPO on the SPID for Conventional Four Wheel Drive.

Martin
I’ve gotten two 465/203 adopters from 74 model K/20 trucks and another from a 75 K/5.

I ran across a foot note years ago on some old GM parts department microfiche that stated the part number for the adapter was good for 74~76 models - that being said I have NEVER heard or seen a 76 model coming with a 465/203; might have just been a part number production info type of thing.
To the best of my limited knowledge that adapter was a 74 & 75 model only option like said earlier.
 
Correct, the SM465/NP203 was '74-'75 only, and it was only with a V8 engine. Although in 1975, the only K series truck you could get a six cylinder engine in was a K20. All 1975 K10 Blazers, K10 Suburbans, and K10 pickups had a V8 engine.

Martin
 
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