My dad is a car guy. He’s had a number of cool ones from the ’60s and early ’70s, but he’s specifically a car guy. In fact, when I was little, he bought an El Camino for work duty, and it has served him faithfully to this very day. And that has sort of always irked me a little: An ElCo is a car with a big open trunk, if you ask me. It’s not a truck; it’s something that can’t make up its mind. I’ve always wanted my dad to have a real truck.
And that’s not to say my family never had a 4x4—my mom had a couple different GMC Suburbans in the ’90s, one of which my parents still own. But my dad has always preferred cars and that’s what he’s driven. When he sold the last of his toys a few years back, I knew it was my time to strike. And now that he’s in his mid-70s, he’s finally relaxed (a little) and has time to do things like enjoy a cross-country drive in a cool GMC 4x4.
I can’t think of a better gift to give him right now than a hot-rod GMC truck. I actually planned on this one being a surprise, but that plan failed when he walked into my garage one day and saw me dropping the new engine into this truck. Finding the right truck and finishing it has taken longer than I thought (three years, so far). But it’s getting close now, and I’ve gathered most of the parts I need. It’s time to finish the coolest truck I could for my dad.
Well, I found the truck. It took me a while, but I tracked down an ’82 GMC 2500 single cab that someone had already modified to a short-bed truck (from a long bed). It was a 2WD and the engine was blown, but the body was fairly clean, the short-bed conversion was done right, and it had a diesel title. I’ll throw in a new fuel-injected small-block Chevy, add a new drivetrain and suspension, and fit 35s, while trying to keep it as low as I can.
I have to stick to one important rule: You don’t build a vehicle for someone else the same way you would for yourself. Examples: I can remember multiple times where a friend got into one of my vehicles and I had to explain, “Hit ‘this switch’ and then ‘push this’ and then start the truck.” Or having to explain to someone how to shift the truck into four-wheel-drive and lock the differentials because there are three shifters and two knobs. Those are just the types of things that would annoy my dad. He’s a car guy, not a truck guy. This has to be a single-key, crank-the-ignition, shift, and go type of vehicle for him to enjoy it. There can only be one shift lever on the floor for 4WD, and any locker engagement better be a simple switch mounted conveniently on the dash. Also, this truck will have to be clean—so clean even his yuppie neighbors will admire it. This has to be something that a hot-rod guy would drive.
This month, the engine compartment is going to see a bunch of new parts, and next time, the suspension and axles are going to be addressed. It should be one killer fullsize GMC 4x4 when completed.
Step By Step
2. Since it needed a new engine block to start, I found an early 350ci block. I had it cleaned up, bored 0.080 over, checked the deck height, and Silv-O-Lite pistons were inserted into the cylinders. A Summit Racing top end kit was applied to the fresh short block. That includes new 170cc aluminum heads, flat tappet camshaft, aluminum air intake, new timing gear set, and all the necessary gaskets.
3. Summit full roller rockers were added to the heads, and Summit Racing valve covers dress up the exterior. Every part on this engine was picked up from Summit Racing, actually. The complete engine build can be found in the April 2013 issue of Off-Road.
4. A Powermaster direct-replacement alternator with the new satin finish looked perfect on the background of an orange and polished aluminum small-block. Every Powermaster alternator is tested and rated before leaving the factory. This one puts out 103 amps at idle and 161 amps when doing highway speeds, and is set to run at 14.8 volts DC. I used a Summit billet alternator bracket kit with an expandable rod end link that allows us to position the alternator correctly and increase belt tension with a wrench.
5. A classic red MSD pro billet distributor and Blaster 2 coil will work perfectly with the Atomic self-learning EFI system I ordered for this engine. It’s a ready-to-run distributor that will plug directly into the Atomic EFI system.
6a. Doug’s Headers were a great choice for a few reasons. First, there’s a nice, thick flange to seal against the head and prevent gasket blowout.
6b. Next, the finish on them looks great. And lastly, they’re a quality header that won’t turn to junk in a couple years.
7 For cooling, I went with a factory replacement aluminum radiator and a Summit Racing aluminum shroud and electric fan kit. I ordered a dual-fan kit, but Summit also has larger single-fan kits if you want one. The fans are made in the USA and the aluminum shroud has nice TIG-welded corners that show off the high quality. Going with electric fans reduces the parasitic loss on the engine caused by a mechanical fan.
8 Mounting the electric fan kit on the radiator required drilling four holes in the top and bottom flanges of the aluminum radiator. Depending on how new or worn-out your drill bits are, this can be easy or hard. Start with a nice, sharp drill bit.
9 While an MSD Atomic EFI kit is eventually going on this engine, it is a self-learning kit, and I don’t want it trying to learn as the engine is being broken in. Alex Kreidl bolted on an old carburetor and plumbed it to the mechanical fuel pump, so we can run this engine prior to installing the Atomic kit.
10 The MSD Atomic TBI kit is an all-inclusive throttle-body fuel-injection system that simply takes the place of an old square-bore carburetor on top of an intake manifold. It’s a self-learning kit that also controls ignition timing. There are only eight connections to be made, and the unit has an integrated ECU and sensors. With the high-horsepower fuel pump kit, the Atomic TBI is capable of supporting 620 horsepower.
11 Most of the sensors and the ECU are held within the throttle body—made to resemble an old carburetor—so not many wires need to be routed throughout the engine compartment.
12 The Atomic’s power module links the Atomic throttle body to the hand-held controller inside the cab and to the wideband O2 sensor. Once the Atomic system has a few parameters to work within, it can start self-learning and adjust as necessary. This power module also has two fan controls for the electric cooling fans that were added.
13 The suspension will be custom built, as low as the truck can possibly sit while still clearing 35-inch Maxxis Trepadors. A little bodywork will definitely have to be done, but with some careful trimming, I think this truck can fit 35s and only ride a few inches taller than a stock 4x4.
14 Next time, we’ll convert this truck to 4WD by removing the front 2WD A-arms, adding Bloody Knuckle Garage radius arms and axle mounts, and using coilovers to suspend it. The BKG arms use large rod ends with 1.25-inch shanks and have brackets that can bolt to most boxed or channeled frames.
15 South Bay Truck is building a Dana 60 with Dana Spicer parts, an Eaton Truetrac, G2 axleshafts, and Reid Racing knuckles. In Part 2 of this “Truck That GM Never Built,” we’ll add this axle into the front end of our GMC using the BKG radius arm kit.