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1958 International Harvester Receives A Technology Transplant (PART III)- Extracurricular Projects

Out With The Old and In With The New


Finally! We have taken delivery of the 2006 Chevrolet Silverado 2500HD drivetrain and components. Some of you may remember PART 1, back in December (To read PART 1 click HERE), when we mentioned one of the most important issues concerning automotive restorations (aside from patience) is staying focused. Over the past few months it has not been easy. All attention and energy is currently being concentrated on the drivetrain and there have been a few setbacks. The drivetrain is what everything else (driveshafts, axles, radiator, exhaust, steering column, etc.) will be looking to for guidance. It is almost as though the engine, transmission and transfer case are the central nervous system. This drivetrain will be in charge of controlling and/or monitoring almost every system throughout the truck. From food intake to forward mobility and in order to know where we can install the digestive system or plug in the arteries we need to make sure the drivetrain is just right. So, it seemed like a natural place to start.

Performing an engine transplant can be easy and interesting (even fun) especially when it’s the same block and head configuration. But this time things were a little different. We were not swapping out a 289 for a 302, we were replacing a 1958 IH Black Diamond straight-6 with a 2006 GM small block V8 … and yes, I was nervous (probably out of my league… and my mind). In performing the operation the idea was pretty basic; pull the old drivetrain out and bolt in the new drivetrain (Sounds easy enough… right?). Well, positioning the new drivetrain as low and as far back towards the firewall as possible, while keeping between four and six degrees of downward angle sounded a little bit more complicated. This scenario, aside from the fact that the new V8 is much lighter and shorter than the original inline-6, would ensure much better handling characteristics than the stock 1958 set-up. So that’s what we set out to do…

EDITOR’s Note: AutoPacific and VehicleVoice staffers are all waiting to ride in Keagan’s IH. Based on his pristine 1976 Chevrolet 1500 pickup (that he won’t let anyone touch) the outcome of this restoration and modification will be outstanding. In its present condition, Keagan’s IH resembles Mater the tow truck in Pixar’s Cars.

To gain access and prevent any body damage we removed the radiator, front fascia, inner-fender wells, quarter panels and hood. We even sent them out for some bodywork while they were off the vehicle. International had been notorious for cutting supplemental or secondary fuel tank filler holes in their front quarter panels and some patch work (without any bondo!) was needed.


After unbolting the motor mounts on the IH Black Diamond Straight-6, removing the driveshafts (F&R), and releasing any cables, wires or linkages we pulled the stock driveline from the frame using a hoist (or ‘cherry picker’). Once the old drivetrain was clear we cleaned and sanded the frame down to bare metal. The frame was then measured and templates were mocked up so that laser cut steel plates could be produced and welded to the inside of the frame rails. Even though the 2006 drivetrain is considerably lighter than the 1958 drivetrain we wanted the frame ‘boxed in’ for structural rigidity. This practice is now quite common and standard with many new production vehicles (e.g. Nissan X-terra, Nissan Frontier, Nissan Titan and GMT900’s (Chevrolet Silverado, GMC Sierra), etc., etc.).

Engine Bay now clean


Frame Boxed for extra rigidity. Holes laser cut to add lightness and provide safe haven for brake lines, O2 sensor wires, and wiring harness


A New Engine, A New Home
Once the frame was boxed, new motor-mount brackets were welded to the frame and new motor-mounts and plates were bolted to the engine block. As for supporting the transmission, a new cross-member was fabricated to accept the Hydra-matic 4L80e while utilizing the stock GM transmission mount. Unfortunately, this particular cross-member had to be rebuilt due to our lack of attention to the transfercase output shaft on the drivers side. Our first attempt at a transmission cross-member was designed and built beautifully but would not have allowed for the front driveshaft to sync between the transfercase to the front axel as it blocked the output shaft on the t-case. (Major Setback and yet another lesson on ‘Focus’!)

Essential Elements
After the drivetrain was bolted into place we wanted to concentrate on the major elements it would need to function properly: Air, Water, and Gasoline. The components needed to utilize these elements were the intake, exhaust, radiator, and fuel tank. The donor engine came with it’s respective ‘mass air flow meter’ and exhaust manifolds but due to fit and finish (…and Federal regulations) the radiator and fuel tank were not included. The easiest and most obvious components were the one’s concerning ‘air’ (the intake and exhaust) so I decided to concentrate on those first.

Air Flow Meter and Exhaust Manifolds
After bolting up the ‘mass air flow meter’ (an important regulator of air into the intake manifold and then the cylinder chambers) I came upon another setback; the stock exhaust manifolds would not fit inside the frame rails. Whoops!
Since most companies that build exhaust systems make most of their money producing headers that will bolt right up to the stock exhaust (Y-Pipe) and custom headers typically cost $800 to $2000 dollars I was not a happy camper. But after about two weeks of research and dozens of phone calls we tracked down some headers, that we were told would fit, some 2000 miles away in Arkansas.

Driver’s side header, primary Tube #1 is resting on the motor mount – preventing the flange from bolting up to the head.

After about a week of waiting they arrived in the mail and as it turns out the passenger side header did fit but unfortunately the drivers-side header did not. It was butted up against the motor mount and dust cover on the transmission which prevented the header flange from being flush up against the ‘head’ (exhaust ports). After sending it back we received a different drivers-side header that did fit. So now the Travelall has a late model Passenger-side Camaro header and a Driver-Side 1967-1972 Chevelle header. Phew…
Water and Ethylene Glycol?
Next on the list was the radiator. The 2006 Chevrolet Silverado 2500HD (donor vehicle) came stock with a ‘cross-flow’ designed radiator and ran almost the full length of the front of the truck (about a foot an a half more than we had room for). So the decision was made to go with the original down-flow radiator only it had to be re-cored with 3 rows of 5/8” tubes (some of the thickest tubes in the industry). The radiator would now have the needed capacity and cooling (even when towing) along with having the proper inlet/outlet tube location, which rely somewhat on engine blueprint and placement within the engine bay.

Final Thoughts
I’m not sure what the next setback will be but I think with every successful phase of the project comes additional impetus to see the project through to its fruition. I will try and tackle the fuel tank within the next couple weeks but it is safe to say that I no longer see an old hunk of junk waiting for the scrap heap; I see a truck with potential.


  • Brad Cornelius| April 1, 2008 at 5:50 pm

    Hey there,
    It’s been just shy of a year since this “Part 3” post. I’d love to see and read about everything that’s happened since then…
    Do tell!

  • Brian Forsberg| December 8, 2007 at 3:34 am

    That has come a long way!

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