K10 to C20 frame

Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.

ptrckdillard

Junior Member
Joined
Nov 27, 2021
Posts
9
Reaction score
5
Location
CA
First Name
Patrick
Truck Year
1973
Truck Model
k10
Engine Size
350
Hello all,
New to the group and Squares, any help is appreciated. I live in the wonderfully over regulated state of CA. I have a 79 short bed K10 as a donor and I have a 73 C20 long bed. My question is, can the front and rear axles from the K10 be put on the c20 without modifications, I know the K member will obviously be removed but was curious if the mounting locations are the same on both frame rails?
Thanks again
 

AuroraGirl

Full Access Member
Joined
Sep 8, 2019
Posts
9,121
Reaction score
6,037
Location
Northern Wisconsin
First Name
Taylor
Truck Year
1978, 1980
Truck Model
K10, K25
Engine Size
400(?), 350
You must be registered for see images attach

not a direct answer but here is a 78 k10 if you wanted some visualization
 

75gmck25

Full Access Member
Joined
Oct 13, 2016
Posts
2,017
Reaction score
1,808
Location
Northern Virginia
First Name
Bruce
Truck Year
1975
Truck Model
K25 Camper Special TH350 NP203
Engine Size
5.7
Rear spring mounts are either 52” spacing, or on a few HD trucks they use 56” spacing. Other than that, the rear springs and axle should directly bolt on. I don’t think there is any difference in the front portion of the frame, but I’m not sure all the mounting holes for the 4WD springs are predrilled.

In that timeframe I think the cab has a removable center section in the floor, and 4WD or 4 speed cabs have a higher “hump” in the floor. I know my ‘75 K25 cab has the removable center floor hump.
 

yepyep

Member
Joined
May 8, 2021
Posts
49
Reaction score
17
Location
the moon
First Name
joe
Truck Year
1987
Truck Model
v20
Engine Size
350 tbi
I know its been done before but i dont think its easy google search k10 frame specs (use image search) ive seen diagrams online somewhere with measurements they are chevys factory diagrams do the same for the c10 and compare.

i did this recently for the rear frame (i had to add a section) but ironically its the only part of the diagrams i cant read are the rear sections so i cant figure out where to drill bumper holes or how long the frame is saposed to be

found these right off but the resolution sucks cant read the dimensions on my phone dunno if this will help you or not
 

Attachments

  • unnamed.jpg
    unnamed.jpg
    36.4 KB · Views: 302
  • unnamed 2.jpg
    unnamed 2.jpg
    39.1 KB · Views: 148
Last edited:

AuroraGirl

Full Access Member
Joined
Sep 8, 2019
Posts
9,121
Reaction score
6,037
Location
Northern Wisconsin
First Name
Taylor
Truck Year
1978, 1980
Truck Model
K10, K25
Engine Size
400(?), 350
Rear spring mounts are either 52” spacing, or on a few HD trucks they use 56” spacing. Other than that, the rear springs and axle should directly bolt on. I don’t think there is any difference in the front portion of the frame, but I’m not sure all the mounting holes for the 4WD springs are predrilled.

In that timeframe I think the cab has a removable center section in the floor, and 4WD or 4 speed cabs have a higher “hump” in the floor. I know my ‘75 K25 cab has the removable center floor hump.
I think bucket has told me before the 4wd swap isnt so bad because most of that is there but going to 2wd would require some work because either rivets or holes for the 2wd crossmmeber stuff would require some measuring and mocking up possibly.
 

ptrckdillard

Junior Member
Joined
Nov 27, 2021
Posts
9
Reaction score
5
Location
CA
First Name
Patrick
Truck Year
1973
Truck Model
k10
Engine Size
350
Thank you all for the input, it's much appreciated. I'll be pulling the body off the c20 soon, so I should be able to find my answer on the mounting points/holes etc for the front. Thanks again
 

eskimomann209

Full Access Member
Joined
Jan 9, 2019
Posts
1,849
Reaction score
1,998
Location
Modesto
First Name
Marcus
Truck Year
1973
Truck Model
C10
Engine Size
5.3
^no punctuation on the moon??

why anyone would ever care is beyond me

I mean, it’s horrible to read. Few areas I had to read twice to decipher the actual meaning.
Punctuation is really important when writing. You know the whole,

I helped my uncle jack off a horse.
Vs
I helped my uncle, Jack, off a horse.
 

eskimomann209

Full Access Member
Joined
Jan 9, 2019
Posts
1,849
Reaction score
1,998
Location
Modesto
First Name
Marcus
Truck Year
1973
Truck Model
C10
Engine Size
5.3
OR..

I mean its horrible to read Few areas I had to read twice to decipher the actual meaning Punctuation is really important when writing You know the whole I helped my uncle jack off a horse Vs I helped my uncle jack off a horse
 

eskimomann209

Full Access Member
Joined
Jan 9, 2019
Posts
1,849
Reaction score
1,998
Location
Modesto
First Name
Marcus
Truck Year
1973
Truck Model
C10
Engine Size
5.3
Thank you all for the input, it's much appreciated. I'll be pulling the body off the c20 soon, so I should be able to find my answer on the mounting points/holes etc for the front. Thanks again
CA technically titles the frame so good call there.
BUT if it ‘twas a me. I’d drill the rivets out of the door jamb and swap the vin plate onto the new cab.
I’d pull the dash pad off the 73 ( no vin notch) and slide it onto the 79 dash to cover up the other vin.
MIGHT even be tempted to pull the windshield and drill out the metal dash rivets and swap the whole cage over. This will eliminate the possibility of someone accidentally finding that old plate.
 

AuroraGirl

Full Access Member
Joined
Sep 8, 2019
Posts
9,121
Reaction score
6,037
Location
Northern Wisconsin
First Name
Taylor
Truck Year
1978, 1980
Truck Model
K10, K25
Engine Size
400(?), 350
I mean, it’s horrible to read. Few areas I had to read twice to decipher the actual meaning.
Punctuation is really important when writing. You know the whole,

I helped my uncle jack off a horse.
Vs
I helped my uncle, Jack, off a horse.
hey man I get it
10$ and a twix bar can go a far way and who are we, as individuals, to say no. warm holes are warm holes. (that was disturbing mental imagery even for me to say lol)
 

AuroraGirl

Full Access Member
Joined
Sep 8, 2019
Posts
9,121
Reaction score
6,037
Location
Northern Wisconsin
First Name
Taylor
Truck Year
1978, 1980
Truck Model
K10, K25
Engine Size
400(?), 350
CA technically titles the frame so good call there.
BUT if it ‘twas a me. I’d drill the rivets out of the door jamb and swap the vin plate onto the new cab.
I’d pull the dash pad off the 73 ( no vin notch) and slide it onto the 79 dash to cover up the other vin.
MIGHT even be tempted to pull the windshield and drill out the metal dash rivets and swap the whole cage over. This will eliminate the possibility of someone accidentally finding that old plate.
wouldnt it be a legaler and also safer in his situation to get the vehicle titled with a new vin so it would be a 2022 or 2021(whenever) with a new VIN attached model year from the california gestapo.
 

eskimomann209

Full Access Member
Joined
Jan 9, 2019
Posts
1,849
Reaction score
1,998
Location
Modesto
First Name
Marcus
Truck Year
1973
Truck Model
C10
Engine Size
5.3
wouldnt it be a legaler and also safer in his situation to get the vehicle titled with a new vin so it would be a 2022 or 2021(whenever) with a new VIN attached model year from the california gestapo.
The way CA wants it is, proof of ownership of both vehicles.
Then they want you to swap the 78 cab onto the 73 frame.
They’ll then attach the 78 vin to the 73 title and scrap the 78.
This can be done legally with bill of sales, titles and a statement of facts.
There is one other form that needs to be filled out I believe it’s form 256.
It’s pretty simple to do.
I just hate the fact that they push the destruction of the “parts” vehicle.
 

AuroraGirl

Full Access Member
Joined
Sep 8, 2019
Posts
9,121
Reaction score
6,037
Location
Northern Wisconsin
First Name
Taylor
Truck Year
1978, 1980
Truck Model
K10, K25
Engine Size
400(?), 350
The way CA wants it is, proof of ownership of both vehicles.
Then they want you to swap the 78 cab onto the 73 frame.
They’ll then attach the 78 vin to the 73 title and scrap the 78.
This can be done legally with bill of sales, titles and a statement of facts.
There is one other form that needs to be filled out I believe it’s form 256.
It’s pretty simple to do.
I just hate the fact that they push the destruction of the “parts” vehicle.
What else is a tyrant to do but make you suffer needlessly and ruin history for their enjoyment
 

Latest posts

Forum statistics

Threads
41,848
Posts
903,425
Members
33,362
Latest member
Dhatch84
Top