Best way to turn my C-20 into a K-20?

[arveetek]

Hey guys!

Since I sold my K-10, I'm now without a 4WD vehicle. I don't do any off-roading, but I need something with 4WD for winter time use and for muddy conditions. I pull a cargo trailer for my business, and sometimes I get into customer's yards and get stuck.

What I would like to do is put IFS under the front of my '81. I know, I know, but I want a smooth riding vehicle. Since I'm not planning to do any off-roading, I thought the IFS would be the best of both worlds...good ride and 4WD.

Another option is to put a straight axle under the front. I didn't like the ride that the straight axle had in my K-10....it rode worse than my 3/4 ton!

The third option is to get a rolling 4x4 chassis and swap cab and bed over. This would probably be the easiest.

I don't want to trade trucks. I love my '81. I've got it set up just where I want it. It runs great, has a strong 700R4 in it, has all the goodies like rear air springs, keyless entry, aux. fuel tank, CD player, etc. etc. I don't want to have to swap out all that stuff.

Has anyone tried to put IFS under an older truck?

Thanks for the help ya'll.

Casey

'81 C20 conversion, 6.2L n/a, 700R4, 4.10's, lots of goodies! Wants to be 4x4.

[ElGracho]

I don't know anything about IFS 4wd except that the hardcore 4wd guys will actually switch from IFS back to a solid axle to get more articulation. I do know that even just swapping frames isn't as easy as it sounds. The cab floor in your C10 will be different than a k10 floor (smaller tranny hump) because the trannys actually sit a bit higher on the 4wd trucks and there has to be room for the transfer case behind that. Regardless of whether you try to swap in a later model IFS or a solid axle you will need to make room for the transfer case, maybe by hacking up your floor pan in your 81.

I guess this is why I have 4 trucks...

[Captkaos]

Cabs are identical 2wd vs 4wd. The hump is higher because the cut the top off and made a taller piece to bolt to it.
The easiest way to make it a 4WD is to sell it and buy a 4wd. I know, that isn't what you asked, but it is the easiest if you plan to drive it.
On the other end of the coin is putting IFS under it. Followed by solid axle. Can IFS be done, sure, is it worth the effort, only you would know. If you don't mind chopping your frame in two, you could get the front section off a 88-up IFS truck and graft it to yours, making sure the alignment of everything is correct. (ala street rod IFS style)

Transfer case won't cause a problem with the cab floor pan either. I have helped chance 3 of these. One was a cab from a truck I wrecked that a friend put on his 4x4 frame.

Your 3rd option would be the easiest in "bolt-on" conversion, but plan on major downtime from swapping everything over... (although you could still drive your current truck, until the big day)

Option 2 (straight axle) is possible, but you have to get alot of stuff that will probably require you getting stuff from a donor frame anyway, which leads back to option 3.

From all the crap I have done, It is my experience that it is alot easier to sell what you don't what to get what you want.

[ElGracho]

Originally posted by Captkaos
Cabs are identical 2wd vs 4wd.

Uhh, not mine. My 84 K10 does not have the bolt in tunnel cover (my 76 C10 4 speed did) and it's tranny tunnel is significantly different (taller, especially on the rear, toward the seat) than my 75 C10, 86 C10 other 86 C10 or my 87 R10.

Another data point, I know that the molded carpet sets from ACC are different 4wd vs 2wd.

[Prerunner1982]

ok.. if i remember correctly the wheel base on a longed reg cab is identical to that of a later suburbans.. you might try. not sure on exactly years though. i dont have the chart handy. its in one of my 4 yrs worth of 4x4 mags i have around here

[neonlarry]

I saw on another message board that someone had some pics of a 1987 c/10 that they had bought, and converted to a 4x4. It actually looked pretty easy, all of the brackets for the 4x4 stuff can be bolted or welded to the 2wd frame without too much trouble. I will see if I can find the post, and if I can I will put a link to it here. I might have saved the pictures of it too, but I can't remember.

[Prerunner1982]

larry....

casey is wanting IFS.. mounting a solid front axle isnt nearly as difficult.

[neonlarry]

I can't find the post, but i do have a couple of pictures of how he mounted the front springs

[Prerunner1982]

larry post them

[neonlarry]

I don't have a way to host them on the web, but I would be happy to e-mail them to someone

[Prerunner1982]

larry when you go to post a message look below the box where you type, you will see the 4 check boxes, look right below that and there is attach file: click browse and find the pic!

[arveetek]

Thanks for all the tips so far!

Right now I'm leaning towards the hardest option....installing IFS. This is a project that would probably have to wait until next summer. Here's what I'm thinking:

Install IFS under the front end: either by swapping over the individual parts, welding a later model front frame section onto my frame, or trying to use an entire late model rolling chassis. I think I'm going to try and use my existing frame. I don't mind drilling, cutting, welding, and fabricating. I can make it work. I'm helping my dad stuff a 6-71 Detroit diesel and Allison auto into his one-ton with custom air ride....we have the skills necessary to make it work.

Install a divorce-mounted transfer case. I love my current transmission, and I don't want to swap it for a 4x4 unit. I helped install a Brownie auxillary tranny in my dad's truck, which is a three speed overdrive. It mounts behind the transmission, with a short driveshaft connecting the tranny to the brownie, and short driveshaft from the brownie to the rear axle. My TC could be mounted the same way. This would allow me to mount it wherever I needed for clearance issues.

I have my truck setup where I want it....I'm not interested in swapping everything over onto another truck. Plus, if I did find an 81-87 rolling 4x4 3/4 ton chassis, it wouldn't have a 700 in it, which I want, so I'd have to swap that as well.....

I'm keeping my truck, it's not an option to get rid of it.

I just wish somebody would tell me, "Yeah, I've done that! It's not hard to swap in IFS!"

[neonlarry]

Well, I tried to attach the pics and it wouldn't work. Anyway, if anyone is interested, they are of a 87 k-10 that was converted to 4x4 using the running gear from a older blazer. You pretty much need all of the brackets for springs, the t-case crossmember, and the 4x4 engine crossmember. The guy that the truck in the pics I have belongs to said it only took a day to do the whole thing.

[arveetek]

In case any of ya'll are wondering, here's what my truck looks like now:

[Prerunner1982]

larry send me the pics, prerunner1982@aol.com

[neonlarry]

Ok, I just sent them

[Prerunner1982]

larry like i said earlier, casey is wanting IFS 4x4, not solid front axle.. he wants a 4x4 system off a newer truck....

[neonlarry]

sorry, I didn't see that post

[Prerunner1982]

its cool.. good pics though... he should have cut off the coil spring pocket though...

[neonlarry]

If I remember correctly it was just built to be a beater, but he was going to swap in a 4x4 crossmember later. I was going to do one just like the pics, but I found a 4x4 I can get for free, so...

[Captkaos]

The only difference is the hump height, which stops before the seat. Once you bolt on the taller hump on a 2wd it is the same and the non bolt in one on the automatic 4x4's.

Automatic 4x4's had a non-bolted hump, manuals had the bolt in hump.

[Captkaos]

Casey,
Based on what you have told us, I don't think this will be too big of a deal for you. Street Rodders do this all the time. I would recommend building a frame jig to keep everything in line. I would just graft a IRS on and build from there.

[ElGracho]

Originally posted by Captkaos
The only difference is the hump height, which stops before the seat. Once you bolt on the taller hump on a 2wd it is the same and the non bolt in one on the automatic 4x4's.

Automatic 4x4's had a non-bolted hump, manuals had the bolt in hump.

I know I'm really taking this further than we need to, but I'm trying to learn something. I think what you are saying is that the manual trucks pretty much all(???) had a bolt in tunnel cover (from the firewall to the seat rise) and there are two different heights, one for 2wd and one for 4wd. Also, the auto trucks have different humps but they don't bolt in. All of my 2wd trucks have the low non bolt in humps and are all auto trans cabs, and my 84 k10 is also an auto truck and has a non bolt in tall hump.

So what does any of this matter? I think if you have a 2wd auto cab, it would at least require cutting the floor to put it on a 4wd truck or make it into one.

Does this sound right?

[PHOENIX]

I have a 2wd w/ manual and the hump bolts in. I love it for changing clutch and tranny.

[Captkaos]

Originally posted by ElGracho
So what does any of this matter? I think if you have a 2wd auto cab, it would at least require cutting the floor to put it on a 4wd truck or make it into one.

If you do a body lift, it isn't necessay. A buddy swapped his without bodylift or hump mods. I would recommend it for access to the top bolts on the trans for R&R.

We are getting technicall now, but all 4 speed cabs with a floor shift have the removeable hump, for R&R also.

4x2 auto small short hump, 4x2 AND 4x4 floor manual - bolted tall hump, auto 4x4- tall solid hump.

All the humps are the same height for the tall ones. The manual are removeable for R&R'ing, the autos are not.

So yeah, you got it......