Salvage Yard Superhero

Reaping high horsepower from a core-charge worthy donor

Story Andy Bolig / Images Jeff Gardner - May 16, 2013 10:00 AM


Gardner Performance Engines began by truing up the block. Here, Andy Gardner line hones the main journals in preparation for our new crankshaft.


 We bored the block (3.800-inch), but while still smaller than a 5.7L bore, we’ve got a few tricks below the piston that’ll help the engine perform.


We used a full complement of King bearings throughout the build. They have proven themselves durable and consistent.


We turned to K1 Technologies for their forged four-inch stroker crankshaft (left). A forged crank is stronger, but heavier. K1 has removed excess material to keep weight down so you don’t pay a weight penalty for forged.


K1 uses special bolts and lube with a degrees-to-tighten method for the fasteners on the rod bolts. Jeff checks all components religiously and commented on the quality of the components.


Jeff checks the crankshaft bearing clearance with a micrometer. The clearances for this engine were .0017- to .0022-inch for the rods and .0025- to .0028-inch for the mains.


Wiseco and K1 Technologies offer a complete rotating assembly (p/n R-KD20112). These pistons will put our stroker 5.3L engine right at a pump-friendly 10.5:1 compression.


Our final configuration uses a 3.800-inch bore with 4.000-inch stroke and 6.125-inch rods, giving our no-longer 5.3L engine a respectable 364ci displacement.


 There WAS an issue with the windage tray due to our increased stroke. We used some washers to give the rods enough clearance to spin freely.


The heart of our engine is the COMP’s LSR camshaft. They feature the most modern lobe configurations for LS engines and are designed for radical street performers. They are designed to make the most of the LS-based, better flowing heads.

Image supplied many of the rebuild-necessities like this Melling oil pump. Jeff centers it by using two feeler gauges to ensure that there aren’t any clearance issues.


Jeff pointed out that we couldn’t forget this little oil director used by the LS family. We want this build to have PLENTY of oil.


To resolve any pan clearance issues, we installed Holley’s LS-retro-fit oil pan. It provides for improved ground clearance, as well as side clearance over many factory pans. It is designed for muscle cars and passenger car applications

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There’s no doubting that the small-block Chevy engine has been on a roll since it was first introduced back in 1955.

The combination of a small package with high horsepower capabilities has wrapped itself with the heartstrings of enthusiasts through generations of both enthusiasts AND engines.

With the latest Gen-5 engines just starting to peer over the horsepower horizon, the current crop of offerings have become prime pickings for those who wish to build upon a great platform and strive for horsepower numbers that were once only reserved for the most extreme of racing engines.

We wanted to illustrate what was possible to enthusiasts if they were willing to commit some time and effort, along with a little bit of coin, to build a great-running street performer. We’ll never argue with the premise “bigger is better”, but we understand that not everyone’s wallets are as big as we’d all like either.

With that in mind, we scoured some of the local salvage yards in search of an engine that would not only provide a solid platform to pump us over the 500 horsepower mark, but also do it without undue strain on our living expenses. The fact that the LS-based engine platform has been around since ’97, and that it has popped up under the hoods of various makes and brands of vehicles in one form or another, make it a prime candidate to start with. Also, all the technology that goes into today’s factory engines only serves to make for a better starting point for YOUR engine build. The advent of CNC machining, coupled with the more stringent controls of emissions and fuel have forced the OEMs to hone their machining processes and standards. Their fine-eyed specification requirements only serve to build a better foundation.

Squeezing 500 horses into six-plus liters has been done with boring regularity. And with the electronic capabilities of today’s engines, it can be made VERY streetable. While plentiful, these larger engines also command more money than their smaller siblings.

Ready to take on a new challenge (and living on limited budgets), we decided to broaden our horizon to include offerings from the truck side of the LS family. The plus of picking from the heavy haulers is that they are very plentiful and they are available in several different displacements. Cost-wise, they can be had for anywhere from $150 to $500, depending on what all you get.

On the down side, many of the components they come with are designed for trucks, so unless you’ve got a huge hood scoop and are putting them in a nose-high, solid front axle dragster, plan on sourcing a new intake and oil pan. Likewise, while you can find lighter versions with aluminum blocks in many family trucksters, the iron block versions are still quite capable. Besides, if you were going to build a “traditional” small-block, chances are at least the block would be iron as well.

We found a solid 5.3L engine for our platform. While we were sure that we could afford the engine, not everyone was convinced that we could squeeze all the horses into the little engine that might. When we spoke to some in the aftermarket about our plans, they were supportive, but in a “don’t be too disappointed if it doesn’t” kind of way. There was only one way to find out.

Granted, our 5.3L engine would soon be one in name only. It was determined early on that if we were going to realize 500hp in a street driver engine, we needed to put some size back in the block. That can be done two ways, boring the cylinders for larger pistons or increasing the stroke of the crankshaft. We opted to use both available options to bring our 324ci engine up to 364 cubic inches of fun.

There are a lot of considerations when stroking out an engine and many involve math and clearance issues. Since our high school isn’t known for its math program, we opted to go with a proven rotating assembly by K1 Technologies and Wiseco. Their good working relationship allows them to coordinate on various combinations that make the best of both companies’ products. Before your eyes glaze over, thinking that such a build is cost prohibitive, you would do well to shop around and see for yourself how cost effective such a swap can be, especially if you’re looking at upgrading the crankshaft in your engine already.

For those who have the “Bigger is Better” tattooed on your thought processes, you’re right. But not only in coaxing more power from an engine. The larger capacity for cubes does several things for a performance engine, and most of them are positive. Coaxing more power is always a benefit for any performance-minded enthusiast, but the larger displacement also allows for that power to be utilized at a lower rpm than a smaller-cubed, higher-revving engine. That has direct benefits for the street driver.

Bigger lungs can also have a calming effect on camshafts as well. We opted for a COMP Cams 281LR HR13 grind (p/n 54-459-11), which spec’d out at .617-inch lift on the intake and .624-inch on the exhaust. Duration at .050-inch is 231/239 with 113-degree lobe separation. This camshaft has a very wide power range and excellent mid-range torque, designed specifically for the larger cubes we will be running.

Forging new ground is never as easy as taking a well-worn path, but there are things you can do to make the trip less hazardous. One way is to follow the lead of those who know the terrain, and when it comes to building an engine, a well-respected machine shop can be your best guide.

We turned to Gardner Competition Engines in East Claridon, Ohio, to do the lion’s share of the build. They work on everything from race engines to custom vintage engines so they know that turning our 5.3L into 500 horses will mean more than part numbers and torque specs. Follow along and we’ll show you what it takes to try and coax more out of less. We'll finish up the top end and do a little dyno time in our next installment, but let's start at the bottom and work our way up!

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