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Alluminum 5.3 Liter Conversion - Leeroy Jenkins

We get current with an all-aluminum 5.3-liter conversion in our beat-up '87 S-10.

Justin Cesler Jun 26, 2012
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Welcome to the introduction of Leeroy Jenkins, our down and dirty LS-10 that's big on getting it done and short on overthinking things. It's a junk truck that we purchased at auction for eight hundred bucks and it's going to stay beat up and reckless for as long as we own it. We've driven it around for months in stock form and had a blast, even with the beater four-speed manual transmission, sloppy clutch, and one-wheel peel open differential. Now, we're not here to brag or anything, but we should mention that our '87 S-10 did come with the notorious Iron Duke TBI engine, which weighs in at a whopping 2.5 liters of displacement. Rated at--wait for it--98 whole horsepower and 132 lb-ft of torque, the Iron Duke was a legend in its day, but, let's be serious, you know that's just not enough anymore.

Naturally, we needed roughly three times the stock horsepower if we were going to drive this S-10 for the long haul and talk about it in the magazine. As you would suspect, the first thing we did was dream up building some sort of crazy twin turbo 408 to run on E85, but that just wasn't in the cards. We're journalists, not millionaires after all. Thus, after many a think tank session (that's code for joking around in the shop for hours on end), it dawned on us that tons of power wasn't really what we needed for this project. In fact, for all of its shortfalls, the old inline four-cylinder did have some admirable qualities, mainly it's durable design and ability to lightly sip on cheap 87-octane for miles and miles at a time. Those two qualities, and those two qualities alone, were elements we wanted to keep with the truck during our upgrades, so it was an easy choice to go with LS power.

Finding an LS engine these days is pretty simple, but finding one in good condition that you can trust for your money is a slightly more difficult task. After some basic searching, we sort of hit a dead end, until our friend Jared Ochs tipped us off to Stu at, also known as Just Chevy Trucks; an operation dedicated to selling swap ready LS engines to enthusiasts. After a quick phone call, we found ourselves on YouTube ( watching and listening to an all aluminum 5.3-liter L33 engine running in a recently wrecked '06 4WD Silverado. With just over 100,000 miles on the odometer and good oil pressure, we were sold, and Stu and his crew were quick to get the L33 loaded up on a pallet and sent our way. When the L33 arrived, we knew we made the right choice. Everything looked to be in good shape and the all aluminum block looked great. Rated at 310 hp from the factory, the L33 wears a set of LS6-esque 799-casting cylinder heads, along with flattop pistons and a slightly higher lift camshaft when compared to regular LM7 iron block engines. At 9.9:1 compression (compared to the traditional 9.5 found in many of the other Vortec offerings), the L33 offers plenty of performance on regular 87-octane, which is exactly what we were looking for.

With the right engine in hand, we needed to make a couple of other choices regarding the powertrain. For the transmission, we chose to ditch the factory four-speed manual box, opting to let a rebuilt automatic transmission do the shifting for us. A quick trip to Monster Transmission and Performance in Brooksville, FL was all it took to get our S-10 hooked up with a Mega Monster 4L65E, which features high performance Kevlar bands, modified drive gears for increased planetary lubrication, and a quality shift kit for firm, snappy shifts. Rated to 650 hp, the Mega Monster SS can handle much more than we plan on throwing at it, which is always a good thing. Commanding the shifts is a Current Performance tuned PCM, while we chose a Lokar shifter from Summit Racing to get us in gear. As for the rest of the drivetrain, well, we're going to throw caution to the wind and just run with what we've got... that's one old driveshaft, an open differential, and a set of 195mm rear tires mounted on 14-inch rims with drum brakes. That should be fine.

Last, but certainly not least, we needed to find someone who actually knew what they were doing to help us put the truck together. This was a no brainer, as Jared Ochs of Current Performance was located just an hour away from our facility and came highly recommended by almost anyone we asked about the LS-10 swap. If you're not already familiar with Current Performance, these are the guys to go to for swap related wiring and in our case, hard parts for S-10 LS swap kits. Jared has been doing this for a long time and stocks everything you need for this swap, including the mount kits, radiators, fans, headers, linkages, and sensors. And, as we said, he and his crew are wiring masterminds, spending a significant portion of their day constructing OE quality harnesses for every LS swap you can imagine. Want to put an LS7 with a blower in a Jaguar? They've got you covered. What about a Honda S2000 or a '33 Ford? Yep, been there, done that. Seriously, if you're looking for swap stuff, check out Current Performance. We did and just two weeks later we were sliding sideways in our LS-powered '87 S-10. Well, not exactly sideways, since we are still on the open "one wheel peel" differential, but you get the point... Leeroy Jenkins is a blast. We can't wait to log some more miles in this truck!

Ghtp 1208 All Aluminum 5 3 Liter Conversion Leeroy Jenkins 02 2/35


Pacific Fabrication
Morgan Hill, CA 95037
Summit Racing
Akron, OH
Kwik Performance
Springfield, MO
Monster Transmission
Brooksville, FL 34601
RMP Automotive Inc.
Port Richey, FL 34668
Current Performance
Port Richey, FL 34668

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