1985 chevy c30 cab and chassis 4x4 swap

[nathanielbenitez]

hey yall so I own a 1985 chevy c30 cab and chassis and I'm looking to 4x4 swap it. I have the opportunity to buy a late 70s early 80s k20 with the 4x4 trans and the complete front end my question is will everything bolt right up? with some modifications and if so what? only wondering before I buy the donor truck

 

[cmichels83]

I am not sure the difference between the C10 and C30 cab, but if the transmission tunnel is the same, you will have to do something to make it clear the transfer case and transmission of the 4x4. I am in the process of body swapping a C10 suburban on a K10 frame and drive train. I went with a 1" body lift, which was enough to make everything clear. However, I am having to fabricate a spacer for the 4wd shift lever to raise it further up to get the shift linkage to operate properly. Some people will cut the tunnel out of the 4x4 and weld it into the 2wd cab floor.

 

[Strick]

There are many things to consider when doing this swap. The C/K30 frame is different than the K20 and the rear axles are very similar but the spring perches and shock mounts are in different places. You having a C&C means that it PROBABLY has a 14FF rear axle in single or dually form...but could also have a Dana 70HD. You can use all the front components but be mindful that the K20 has a 10 bolt front axle that is the same as a K10 truck; less the 8 lug outers and possible gearing. The transmission tunnel in the cab presents some problems as well. If your truck is a manual transmission and the donor is as well then you will be ahead in your swap.
Look around in these forums as I have seen some folks post some real technical info on the cab floors, spring perches and axle swap info. Good luck on the swap and share some pics of the journey.

HS

 

[AuroraGirl]

There are many things to consider when doing this swap. The C/K30 frame is different than the K20 and the rear axles are very similar but the spring perches and shock mounts are in different places. You having a C&C means that it PROBABLY has a 14FF rear axle in single or dually form...but could also have a Dana 70HD. You can use all the front components but be mindful that the K20 has a 10 bolt front axle that is the same as a K10 truck; less the 8 lug outers and possible gearing. The transmission tunnel in the cab presents some problems as well. If your truck is a manual transmission and the donor is as well then you will be ahead in your swap.
Look around in these forums as I have seen some folks post some real technical info on the cab floors, spring perches and axle swap info. Good luck on the swap and share some pics of the journey.

HS

the K20 having C6p or not would be very important to know here


The late 70s k20 wouldnt be c6p but would possibly have a dana 44, and an early 80s would be 10 bolt


need to know more about the OPs possible donor

 

[bucket]

the K20 having C6p or not would be very important to know here


The late 70s k20 wouldnt be c6p but would possibly have a dana 44, and an early 80s would be 10 bolt


need to know more about the OPs possible donor

C6P or not, it doesn't matter.

A K20 is going to have different rear perch spacing and different spring hangers, along with different hanger mounting pattern than a C30.

A K20 will also have a 10 bolt or Dana 44 in the front, not the Dana 60 that would have been found in a K30.

A C30 will have slightly different frame rails up front, compared to a K30 and both will be a little different from a K20 frame.

It can all be swapped over, but it definitely doesn't just bolt up. It will take a lot of work and the end result will be a K20.

 

[AuroraGirl]

C6P or not, it doesn't matter.

A K20 is going to have different rear perch spacing and different spring hangers, along with different hanger mounting pattern than a C30.

A K20 will also have a 10 bolt or Dana 44 in the front, not the Dana 60 that would have been found in a K30.

A C30 will have slightly different frame rails up front, compared to a K30 and both will be a little different from a K20 frame.

It can all be swapped over, but it definitely doesn't just bolt up. It will take a lot of work and the end result will be a K20.

but a c6p front axle would have more desireable ratios (that I presumed he wanted) and bigger springs wouldnt it? Thats where I was going with that

 

[bucket]

but a c6p front axle would have more desireable ratios (that I presumed he wanted) and bigger springs wouldnt it? Thats where I was going with that

Not necessarily. I believe 3.73 and 4:10 were still the most common. I believe you could also get C30's with a 3.21 ratio. Of course there were differences from year to year though.

It really doesn't matter though, as swapping a C30 to any kind of a K is going to be far more of a challenge than a simple gear swap.

 

[Strick]

I like to see what I’m working with before working on it. I’ve messed with enough of this stuff to realize that sometimes leftovers were used regardless of the RPO or SPID. We also have to be reminded that changes may be made after-factory in the 45 years after manufacture. Look closely here and tell me what is different or “ain’t right” as we say here in the South. 1978 K25 Sierra.

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