4x4 floor hump
 

I am getting ready to put a 79 2 wheel drive cab on an 84 4x4 frame. I was gutting the 84 cab last night, pulled the carpet out, and was very surprised the find the high hump was formed into the floor-clear back under the seat. When did they start doing that? I was expecting a bolt-in hump that I could install in the 79 cab, after cutting the floor in the 79 cab. The frame has a 700r4 and a np207(I think that's what it's called). If I find a bolt in high hump out of and older square body, will that give me enough clearance? I have all of the tools and knowledge to cut the floor out of the 84 cab and put it in the 79-just not what I really wanted to do. Any suggestions? Thank you.

Re: 4x4 floor hump
 

My 83 K30 had the bolt in but all the CUCVs I've ever had ('84-'87) were one piece high humps.

Re: 4x4 floor hump
 

I need some educating-what makes a truck a CUCV? My 84 was a 6.2 diesel half ton Silverado.

Re: 4x4 floor hump
 

cucv is a special military vehicle. 24volt system, etc.

Re: 4x4 floor hump
 

For the Chevy squares, M1008 CUCVs are 84 model K30s with the 6.2, TH400, and 4.56 gears. Mostly stock 12V system with several 24V add-ons to allow the truck to work with the other NATO standard military vehicles. M1009 are Blazers with similar treatment.

There are several variations on both vehicles to meet various military needs.

While the series was purchased from 84-86, most vehicles were built to 84 standards to avoid supply chain issues.

Re: 4x4 floor hump
 

Worst case scenario, you'll have to weld the high jump into the the other cab floor. You wouldn't be the first to do it. Maybe you'll get lucky, and find a bolt-on hump.

Re: 4x4 floor hump
 

Yep. It's not rocket science. But the bolt-in humps are pretty handy.

Re: 4x4 floor hump
 

Around here some people used a 2" body lift to avoid cutting such a large hole in the floor. There was a thread here in the last few months where a guy used a 2WD cab with no body lift and it cleared everything. I plan to put a 2WD cab on my K20 this summer and I will try it without the body lift to see how it fits. I have never been able to fix anything through the bolt on hump anyway so I doubt I will miss it.

Re: 4x4 floor hump
 

From what I’ve seen, they quit making the hump bolt in around 84 or 85. I did the same thing you are doing. I put a 2wd cab on an 87’ 4x4 frame. I found a bolt in high hump tunnel out of a rusted out 83’ 4x4 cab. There was plenty of clearance for the transmission.

Re: 4x4 floor hump
 

Did your truck have a body lift on it? I'm not much on body lifts. Does your truck have auto trans and NP208?

Re: 4x4 floor hump
 

The high hump mainly provided clearance for the shifter for the transfer case, or for a standard shift transmission. almost all 4x4 trucks I have seen with the low hump cabs had an automatic, and had plenty of clearance. if anything, you may need to locate the 4x shifter further to the right to help clear the automatic.

you could make the weld tunnel a bolt in one by simply drilling some holes in it. the overall shape of the tunnel did not change that much.

Re: 4x4 floor hump
 

No lift. I originally had a 700r4 and np208. Currently has a th400 and np208. No difference in fit with either transmission. Here’s a pic of mine.

Re: 4x4 floor hump
 

my 84 k20 had the solid floor pan not the bolt in