Cab swap 89 to 92 has anyone done it and did you have any issues?

[jmig]

Debating on buying a 92 c1500 and performing cab swap on my 89 dually. First off it's not a oobs so the body style is the same, more concerned about the existing wiring in the donor cab. The donor currently has a 305 and my dually has a 350, overall the interior and exterior are in great shape just a little concerned about if its plug and play as far as the harness' are concerned.

If anyone has and first hand knowledge please let me know.

 

[someotherguy]

The dash harness is not the same because the gauge cluster is very different electrically 88-91 vs. 92-up. Doesn't even use the same connector. The dash shell is slightly different between those years where the connector for the cluster goes, including a raised standoff area for 92-up connector. My suggestion? Either move your dash over complete with wiring, or go ahead and upgrade to the new cluster setup by leaving the dash in there.

Additionally, the hole on the passenger side of the firewall is square on the 88-90 and changed to rectangular on 91; the harness to the ECM/PCM has a plastic block there which attaches to the firewall as a keeper of sorts. It's not a connection point like the driver's side has; it's just to retain the harness in the correct spot and fill the access hole. Not a huge problem but if you want it to be 100% pristine you have a little work to do. Can't remember if that plastic block can be swapped out with the other one or not; it's been a while.

If the truck is ever registered somewhere that requires smog tests you'll run into trouble as it will now appear to be a half ton with a 305, according to the VIN tag on the dash...removing or changing it is illegal.

Richard

 

[jmig]

Thanks for your insight and knowledge as always. As it sounds I will have to strip and relocate the wiring out of the existing cab to reuse it in the 92 because I want to use the current interior set up in the 92 as it is all gray with power windows and locks. I will wire up the DRAC as I did in my 88 and should be good to go.

As for the VIN tag I am concerned as it isn't tagged or titled yet and want to switch it as it it will have to match for motor vehicle purposes. To help with this I do have a "friend" that will inspect it for me as the laws here have changed for Historic/Street Rod tags.

 

[someotherguy]

Just keep in mind it's illegal for you to alter the tag on the dash regardless of reasons. It sounds stupid but think of the loopholes opened up to thieves if any modification of the VIN tag was allowed.

A friend of mine made an extended cab 3500HD GMT400 (never existed from factory) and wanted to keep the VIN tag correct, not only for legal reasons but also so that the GVWR is correctly listed according to the VIN because it's a heavy duty truck and will continue to be used as one. To accomplish this he kept the forward portion of the original cab, chopped it mid-A-pillar, and grafted on a 3rd door extended cab. A lot of work but cake for him as he's a body man.

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Never any issue with the VIN as it has never been touched. The only discrepancy to be found would be if someone really wanted to decode the VIN and saw it indicates a 2 door cab.

Richard

 

[jmig]

I know switching the VIN tag is illegal so I will find out what is typically done here in Maryland and may reconsider and just swap parts over to my existing cab but it would be a cleaner finished product if the cab swap was done. Thanks again!