I have a 1975 Chevy (Crew Cab) 3/4 ton 2 wheel drive, which currently houses a 1972 402 BB and a 4 spd manual with a 14 bolt corporate rearend (4/10 gears). I am converting the truck to 4X4. I would like as much input from you guys as possible to insure no stone is left unturned and I do this right.

I am piling up my parts in my shop as I find them and reconditioning as needed. Here is what I got so far:

3/4 ton 10 bolt GM front axle (4/10's)...needs work.

400TH that I want to use with the NP203 which requires a short tailshaft. The 400's probably toast so I'm going to use it for a core trade in on a factory reman with short tailshaft. I'm also getting the conversion gear/lockout hub kit for TC.

I am currently building a 350 4blt main .060 over with an RV cam, and probably some bolt on stuff like intake (torquer got it for $40),Carb probably 700 Edlebrock?, headers, & hot ignition. This is a short term engine until I complete my long term goal a 383, I already have a block that's checked out good.

As well I have a complete 77' Chevy 1/2 ton 4X4 truck (not a Crew Cab) for parts to complete the conversion process.

What else do I need to think about?

Its cheaper just to buy a 4x4, your looking at a new tranny, transfer case, front axle, driveshaft, a 2wd floor is different than a 4x4 so I imagine some type of lift kit to clear the front differential. I'm sure there some other stuff I couldn't think of but I'd say for the buck, go buy a 4wd.

You could be right, and if you could find me a 3/4 ton 4x4 Crew Cab ranging from 73' thru 83' that's not a dually, that is in fact for sale, which most are not or they are so junked out they are not salvagable then I would but it.

But I have to work with what I can find, I have been searching for this particular model of truck for around 10 years, and in that time I have only found four, two that meet these spec's and both were not for sale, one 2 wheel drive that was junk and over priced and lastly the one I currently own,reasonable price and in good working order. So I have chosen to do the conversion because I cannot find the truck I want.

I already have all of the parts you mentioned, minus the driveshaft which I will have custom made.

What I need to know is what mods need to take place to complete this conversion, other than what has already been mentioned or that one could assume I have considered based on the parts list I have provided.

I am also considering a change to 4x4 on my 80 Suburban. I have a donor 82 Jimmy for all the parts and wiring I wanna put in the Jimmy's Diesel V-8 as well. The Jimmy runs the best and I want to keep all the 4x4 by putting it on my Suburban. Ive been told everything will just bolt up but will take a long time to do.
Anyone done this?

I beleive the frame towers and the wiring harness for sure will have to go in the burb, propably some other things as well cross members somelinkage etc..

I figure the wiring will be the big challenge to do correctly. I have plenty of black tape and torch gas so I feel at least somewhat prepared. I figure the only real prob will be the rear propshaft; and I can make that in a lathe. Time I get done, Diesel fuel will be $3.00/gal. my luck. I think it will pull pretty good; I haul a bomber to a local track and the anemic 350 gas just don't got it. That and being 4x2 I'm always stuck if it's muddy. 4x4 Suburbans are unheard of here and Im gonna have one.

What transmission and transfer case are you using?

I dont know much about transfer cases, but like most it has 4 high, 4 low, and neutral positions as well as 2 x high. Manual shift in the floor and manual hubs. If I had to guess, I'd say prob a New Prossess 205.
The transmission is a 1982 700 R-4, redone by a competent shop 2 years ago. ( M&M Transmission, Mount Vernon Ill., 62864.)
If I don't get on this real soon, winter is gonna hit me in the rear and make it no fun!

looks like NO FUN to Begin with dude!! I agree..find a donor...no matter what year and make the change over to 4X4 that way. You just might have better luck with this in a truck/4X4 forum....just a thought.


Tazz


Rat Rods Rule!

Well, I gone and done it!

I cut the stub out of my suburban yesterday and am gonna put the stub from my jimmy in real soon. A couple of little things to fix and convert I hope to have the stub welded in and the chassis rolling tonight. Cutting the frames was the only real way to go; so much easier.
A little wiring and I will present the 6.2L diesel/'700-R4/np 203 combo as a unit and measure for a driveshaft. I was pleased to find the floor is a bolt in change, makes the shifter easy.
I wonder if anyone makes a little roots-type blower for this thing...

What cutting did you have to do?

I cut the frame right behind the first body mount (under front passenger's and driver's feet) on the suburban; and the same but a foot further back on the jimmy. The jimmy's rails were then trimmed to leave only the sides of the frame rails, without the "boxing" channels on that extra foot. These "overhangs" will go inside the suburban's channeled rails, leaving the top and bottom "boxing" parts to butt together. There are holes present in the rails to center up on so I can get it all straight before MIGging it all back together. The diesel's Hydro-Boost system and steering assist pump were left on the stub; I just removed the booster/master cylinder from the firewall and set it down. Once centered and back in the body and core support mounts, the fuel lines and rear brake line will be a simple matter; they join at factory points.

The wiring harness change was a snap. If anyone is "afraid" of this part, (I was) don't be. It is a simple bolt-in. Painless.

I still have the rear end to tackle, but I dont think it will be too bad. I am going to have to make a custom rear propshaft; mine is a stepped tube and cannot be shortened enough.

Well, the stub was easy compared to changing the rear leaf springs!
Why G.M. didnt anti-sieze the spring bolts is beyond me; it's next to no way to get them out. I will have to move the rear shackle brackets forward on the frame rails( the holes are allready present) to mount the shorter and taller jimmy leafs. Grade 8 hardware will be used throughout; and tons of anti-sieze.

I did convert a 79 chevy 4x2 to 4x4 using a Blazer donor. I did it a little different though. The motor on the Blazer was toast, but the 6cly in the P/U ran great. So I left the motor and swaped the transmission, xfer case, front and rear ends. Took about a week full time. Almost everything was bolt up. I was amazed at how everything was identical between vehicles. The one thing that hit was the transmission tunnel, it wasn't big enough for the xfer case.

I thoug ht I was the only one wacky enough to do it. Good luck to you.

That sounds about how my project is going, I installed a body lift that will most likely take care of the TC clearance issue I will find out soon I am almost ready to put Trans and TC in (I am doing it in stages, the front axle is last). What did you do to resolve that issue.