1981 GMC Jimmy Build

[ryan22re]

I've noticed this is mainly a Jeep forum, but here's my build up of my 81 Jimmy.

I started collecting parts before I even had a truck. I started with a sm465/208 combo, and a 3/4 ton 14 bolt rear. I rebuilt both the 465 and 208. Made a "short" shifter for the 208 that I could reach without touching the floor, and a shift knob to hold a hand throttle.

 

[ryan22re]

I welded the spiders for the 14 bolt, and shaved the 14 bolt housing. Welded the tubes to the center section, along with the plug welds, and converted it to disc's.







Bought 20 37" military goodyears and kept five for the truck.

 

[ryan22re]

Then, in October of '09 I found a truck. I got it for $300 off of craigslist in Monroe, NC. Story is that a lady bought the truck for her old man, and he got drunk and lost the keys. He left and she was getting evicted and needed it gone. Somewhere in there the thing was buried in some mud, and bent a rod. Used a test truck from work to bring it home.



Pic taken around lunchtime in Pageland, SC.



Back home in Irmo at the old house around 1 pm.



Around 5 pm that night.

 

[ryan22re]

After tearing down the 350 this is what I found:





Broken piston, bent rod, rod bearings so gone, the piston would hit the counterweight on the crank and make a terrible squeaking sound. Did run enough to get it off the dolly and into the driveway.

 

[ryan22re]

I called a buddy to see if he had an engine laying around, and he ended up giving me a 305 (was more of a trade, I had given him some engine parts years ago when I left the dealership). It's an 88ish model which means it has goofy center bolts on the intake and no provision for a block mounted fuel pump. Had to do something about the intake and a fuel pump.

I made a drill guide to redrill the intake on the center holes to the 72* that these heads require (vs standard 90*).



Cleaned the engine from this:



to this:



Stuck the engine in around Thanksgiving that year and got it running again. By the time I had a running truck, with all the parts and tags and registration and what not I had about $700 in the truck.

 

[ryan22re]

I also drilled the intake and made an thermostat adapter to allow for four corner cooling. This lets the air and coolant out of the back of the engine to circulate to the front.









I didn't paint the engine cause I plan on a 350/383 on propane build (for which I have most of the parts).

 

[ryan22re]

I then cleaned off of all of the JCWhitney crap off of the truck. Looks like during the 90's somebody called JCW and said "yes". Only thing missing would have been a bug shield and a lund visor.



Ripped out the interior and cleaned the mold and mud out of the truck. Check out the fabric on the seats. This thing was pimp in 1981.





One of the reasons the truck was so cheap:



Rockers are gone. Plan to replace them with some heavy box tubing and mini boatsides.

 

[ryan22re]

I bought a 3/4 ton dana 44 w/ 4.56 gears and 4.56 gears to go in the 14 bolt. I spend a pile of money and time on the dana 44, and when I went to put it back together I found this:



Decided to cut my losses and buy a 60. Found one in Winston-Salem for $800. Came with a matching 14 bolt and 4.10 gears. Sold the extra 14 bolt (without the gears), most of the dana 44 parts (just took the empty housing to the scrapyard today). Rebuilt the kingpins, welded the spiders. Swapped the 4.10 gears into the 14 bolt.

 

[ryan22re]

Put a 1" body lift and polyurethane body bushings on the truck to make way for the new rubber.



Trimmed up the body and bumpers some:



Mounted some cab clearance lights behind the grill due to the fact that the original turn signals were in the bumper (which I cut).

 

[ryan22re]

Bought some wheels (16.5x10's) and welded some reinforcements to the beads. Will act as a bead lock with the 16.5's aired down. Cost $19 for the material (3/16ths steel rod).









The four wheels on the truck were tig welded, the spare I welded at home with my trusty stick welder for proof of concept.

 

[ryan22re]

Got rid of the top, tailgate and doors. Lost 500 lbs easy. Made some tube doors out of 2" .090 DOM and some mirror brackets that bolt under the fender bolts.

 

[ryan22re]

If memory serves me right, this brings us to around Memorial day week in '10. Had all the wheels, tires, axles ready to swap in. Good thing about K5's is that tons are a bolt in. Shoved the axles under and cut the front fenders.

Rear done first:



Then the front:





Dana 60 also has a beefy tie rod with 3/4" rod ends.





Cut fenders:

 

[ryan22re]

After the swap to tons, drove it around town for a little bit and then started swapping in the 465/208 combo which is also clocked flat. Stock transfer cases hang down a lot on these trucks. Also threw in some seats from the pull a part.







Hole I ended up cutting to fit the clocked up t-case and support rod.

 

[ryan22re]

Bought a clutch pedal and made my own linkage. Uses 7/16ths rod ends and tubing with the stock pedal and z-bar.

 

[ryan22re]

Shifters with hand throttle:





And the crossmember and skid I built for the clocked up t-case:

 

[ryan22re]

Patched the hole in the floor and built a 2 1/4" into 3" exhaust.

 

[ryan22re]

Made a dual snorkle air cleaner.



I also used a big master cylinder from a 99 P30 van to work with the disc/disc set up. Bought a tow rig too. Was planning on making it "streetable" to drive back and forth to the trail. Decided to buy a DD that could serve as a tow rig as well. 04 Superduty with a 6.0.



And that's about it for now. Truck has no front driveshaft, the diff hits the exhaust (front axle needs moved forward) and is driveable otherwise.

I plan on lots of things, like rockers/boatsiding, full hydro steering, moving the front axle forward, bigger tires at the same ride height, narrowed front and rear, and a rollcage. Just bought a new house in Lexington. Progress will be slow, but plan on doing something with the rear bumper and a propane conversion next. I have a 350 ready to be built into a 383 to replace the 305.

 

[Brianwmiller]

Hey man the names Brian Miller. I live in irmo use to see you running around great looking truck!

 

[Steve97tj]

I love k5s always thought they were cool as ****.

 

[Feileod]

Makes me want to build a M1009 CUCV Blazer even more. Nice build man, impressive.