In the world of performance engines, “There’s no replacement for displacement” is one of those old sayings that still gets thrown around like gospel. But Late Model Engines (LME) out of Houston, Texas, is about to put that idea to the test in the third running of the LS Vs. Coyote competition. Their latest entry isn’t a monster-cube stroker, nor is it based on one of Chevrolet’s big-inch LT or LS powerplants. Instead, it’s a 5.3L Gen V L83 engine, a configuration Chevrolet puts in its work trucks and calls the EcoTec3 5.3L V8, that’s being purpose-built to go head-to-head against a 5.0-liter Ford Coyote built by Fast Forward Race Engines in our unique drag-and-drive contest.

At the helm of the build is LME co-owner Bryan Neelen, who’s spent more than two decades turning modern GM V8s into horsepower-making works of art. “This build is not our norm,” Neelen admits. (Ed. Note: that’s because we asked him to build a 5.3L to more closely match the cubic inches of the 5.0-liter Coyote.) “We almost never do 5.3L LT builds, but we approached it with the same principles and precision we use in our high-horsepower LS and LT programs.”

The block may be stock, but nothing that goes into it is. This is Manley’s Pro Series forged steel crankshaft with the stock stroke. It is a non-twist forging, which improves strength, is shot peened, and magnafluxed for any cracks before it leaves the factory.

LME started in 2003 as a cylinder-head porting shop. Back then, the LS engine was just hitting its stride with enthusiasts, and LME’s hand-ported heads and camshaft packages were helping customers push the limits of stock bottom ends. As more power meant more broken engines, LME evolved and added complete engine assembly, precision machine work, and eventually in-house manufacturing of billet and cast performance parts.

Today, the company employs more than 20 people and runs ten CNC machines with dedicated departments for component manufacturing, cylinder head development, and engine assembly. LME supplies everything from heads-only packages for speed shops around the globe to complete, custom engines for racers and horsepower fanatics.

Summit Racing-supplied Clevite bearings are used throughout.

While LS builds are still part of the business, Neelen says the majority of its work now involves Gen V LT engines. “We’ve actually passed the point where we build more LT engines than LS,” he explains. “The LT market is huge for us.”

Why a 5.3L?

Given the choice, most builders aiming for all-out performance would start with the LT1 or LT4’s larger displacement. But in the interest of fairness, the Coyote vs. LT contest has strict rules: Both sides must stick with their factory bore and stroke. And in the interest of keeping the displacements relatively equivalent, LME was asked to work with a stock 5.3L LT block.

Custom 3.800-inch strutted pistons from Diamond were chosen for this build because their design could hold up to the extreme combustion pressures created by the turbo while keeping the rotating weight down

Even though one of the strengths of both LS and LT engines is the ease of punching out big cubic inches, we think the smaller 5.3L still stands a chance in this competition. So the 5.3L aluminum block, which can be found in many late-model GM trucks, was sourced from a local core supplier. “You can get them for relatively low cost,” Neelen notes. “That makes them an interesting option for budget builds, though ours is far from a budget build.”

Since they couldn’t take advantage of big cubic inches, matching the Ford Coyote’s high-revving nature became LME’s top priority. “Our whole goal was to turn as much RPM as possible,” Neelen says. “With similar displacement and turbo size, the way to level the playing field was airflow and RPM.”

LME’s Vinnie Monighetti checks the bearing clearance on the Manley I-beam connecting rods that will connect the crank to the pistons.

Gen V 5.3L — L83 Aluminum Block and Heads

While LME starts with a stock block, everything else inside is premium aftermarket hardware. A Manley forged 4340 crankshaft with a 3.622-inch stock stroke swings 6.125-inch Manley forged 4340 steel I-beam rods and custom 3.800-inch Diamond pistons with a direct-injection delete dome profile. Clevite bearings keep the rotating assembly spinning smoothly, and the pistons wear a heat-reflective coating straight from Diamond. An ATI Performance LT4 Super Damper manages all the harmonics of the rotating assembly.

Interestingly, LME chose not to sleeve the block. “Sleeving strengthens the bore but weakens the main webbing,” Neelen says. “We’ve seen sleeved production blocks crack in the main web area at high horsepower. Plus, for this project, we wanted to keep it relatable, something a guy could replicate without extensive block work.”

Here’s a look at the heat reflective coating on the top of one of the Diamond pistons that’s already in the bore. A stock DI piston has a divot that can impede the flame front in a port-injected engine, so these pistons have a custom profile that optimizes port injection on this LT engine.

One block modification is a clever upgrade to the oiling system. The LT’s factory oiling path routes oil through a series of 90-degree turns before reaching critical areas, which isn’t ideal when you are operating at high RPM. LME re-engineered the system to provide a straighter, more flow-friendly route.

Holding the oil is a GM COPO Camaro drag race oil pan. From the pickup, oil flows through the pump, exits via a -10 AN fitting to a remote filter, then re-enters the block just above the pan rail — bypassing the long main oil galley and its sharp turns. “It’s a little trick we use on dry-sump builds, adapted for this wet-sump setup,” Neelen says.

Monighetti puts the finishing touches on the 5.3L short-block in LME’s absolutely spotless assembly room.

Sealing the cylinder heads to the block are ARP head studs and Cometic MLX gaskets. The LT’s stock cylinder heads received LME’s latest CNC porting program to maximize airflow into the combustion chambers. For this build, they also went a step further by installing oversized seats and valves. The intakes are now custom Manley 2.060-inch titanium valves, while the titanium exhaust valves measure out at 1.580 inches.

In the old days, stuffing that much valve into a smaller cylinder bore (the 5.3L’s cylinders are just 3.780 inches in diameter from the factory compared to the 6.2 liter’s 4.065 inches) was a great way to shroud the valves and actually hurt airflow. But, with the canted valve design of the LT’s cylinder heads, the valves are actually angled to open toward the center of the chamber, so this becomes a big improvement.

Instead of the stock style roller lifters in plastic trays, LME chose to go with COMP Cams’ Evolution lifters that maintain proper alignment by using tie bars. They will ride on a COMP hydraulic cam with 0.648 inches of valve lift, 254 and 268 degrees of duration at 0.050 tappet lift, and a lobe separation angle of 119 degrees.

LME also converted the heads to accept LS-style spark plugs. “LT plugs protrude further into the chamber and have fewer heat range options,” Neelen explains. “By machining the plug boss deeper for an LS plug, we can run a #10 heat-range NGK, which is better for turbos and big boost.”

The combustion chambers were also softened to slow the burn rate, a tuning-friendly move given the engine’s relatively high 12.5:1 compression ratio.

The stock LT heads received significant port work via CNC machine to maximize airflow.

Valvetrain Stability: Tie-Bars Over Trays

LME worked closely with COMP Cams to design a custom-ground camshaft and matched valvetrain. The cam carries 254 degrees of intake duration and 268 degrees of exhaust (both at 0.050 inch of tappet lift), a 119-degree lobe separation angle, and 0.648 inch of lift. Titanium intake and exhaust valves from Manley paired with Comp’s aggressive conical springs help keep the valvetrain under control all the way to LME’s 8,500-to-9,000-rpm target. “The conical springs give us 165 pounds on the seat and 540 open,” Neelen says. “They’re lighter than dual springs, which helps reduce mass at the rocker tip. That’s critical for stability at high RPM.”

For lifters, LME chose COMP’s Evolution hydraulic rollers. This is significant because the Evolution lifters use tie bars, so you can ditch the factory plastic lifter trays, which are designed to keep the stock rollers from spinning in the lifter bores. “We never like to rely on plastic to control such a critical part,” Neelen says, especially when pushing the valvetrain to its limit like he plans to do with this 5.3L.

Of course, high-flowing ports are useless if the air and fuel can’t make it into the combustion chambers, so the valve sizes have been increased to 2.060 inches for the intakes and 1.580 inches for the exhausts (up from 1.928 and 1.556, respectively). They’ve also swapped out the steel valves for lightweight titanium units.

Both Active Fuel Management (AFM) and Variable Valve Timing (VVT) were also deleted. AFM ports in the valley were tapped and plugged, while VVT was removed using LME’s own cast-aluminum front cover and cam gear kit.

Feeding the Beast

The engine breathes through a Holley Lo-Ram intake manifold topped with a Holley 105mm throttle body. And to help keep the intake temps under control, a Tick Performance air-to-water intercooler is integrated between the upper and lower plenums. The intercooler is designed for Holley’s Hi-Ram, so LME ended up with some light machining on the Lo-Ram’s lower plenum to make it fit.

In order to help meet the goal of a 9,000 rpm redline, LME installed lightweight conical valve springs from Comp Cams with 540 pounds of open pressure. Notice that lash caps have been installed to protect the titanium valve stems from the force of the rocker arms.

Port injection replaces the factory direct injection, using block-off plugs from ICT Billet in the DI ports. “For drag-and-drive, there’s no reason to run dual fuel systems,” Neelen says. “Port injection is simpler and more cost-effective here.”

Before the turbo system goes on, LME validated the combination naturally aspirated on VP C16 race fuel. The result was a very impressive 608 horsepower at 8,500 rpm, serious output for a small-cube engine in NA trim.

That high-revving character will be key once boost is added. “Horsepower is just airflow and RPM,” Neelen says. “If we can match the Coyote in those areas, we can be competitive.”

Both the Active Fuel Management and Variable Valve Timing systems have been deleted, so the stock valley and timing covers have been replaced with pieces from ICT Billet and LME.

LME’s Constraints and Strategy

When the rules mandated factory bore and stroke, LME lost the chance to run a big-bore, short-stroke setup that might have further favored operation high in the RPM range. “We initially wanted to go max bore and adjust stroke to hit the cubic inch limit,” Neelen says. “That would have helped de-shroud the valves and build a more dedicated race engine. But we adapted.”

Another challenge is that Coyotes can make serious power with stock cams and unported heads, keeping their build costs lower. By contrast, LME’s LT build runs nearly all aftermarket internals and fully worked heads. “In some ways, the Coyote can be more economical. Unless you start replacing everything in the valvetrain, then it gets closer,” Neelen says.

A calling card for the LT engine family is direct injection for the fuel system. It’s helpful when it comes to meeting government emissions standards, but not as much when you are trying to make big power. LME is going with a port fuel injection system and the ability to flow tons of fuel through an electric pump, so they’ve used a set of plugs and a retaining bracket from ICT Billet to seal off the injector ports.

The turbo system will feature an HPT Turbochargers unit sized to the rules. It will be installed for the next phase of testing. Neelen expects the combination of high compression, efficient airflow, and robust bottom-end parts to deliver competitive numbers while surviving the abuse of a drag-and-drive event.

“We’re rolling the dice a little with the compression, but we’ll tune conservatively at first and work up,” he says. “The goal is to run hard and finish the event, not just make a hero dyno pull.”

In naturally aspirated form, this little LT made a stout 608 horsepower on LME’s engine dyno. Once the turbo is hooked up and pushing boost through the Holley Lo-Ram intake manifold and the Tick Performance air-to-water intercooler, the sky is going to be the limit.

This 5.3L LT build may be a one-off for the contest, but we’re still very interested to see how LME’s expertise with the LT family in general will work to maximize the little engine’s potential. By applying the same meticulous blueprinting and high-RPM strategies they use in bigger builds, they’ve created a small-cube package that’s both unique and competitive.

“It doesn’t matter if it’s a Ford or Chevy,” Neelen says. “They’re all air pumps. If you understand airflow, RPM, and durability, you can make anything run hard.”

The next time we check in with this engine, it’ll have a turbo hanging off the front and ready to prove what it can do under boost. Whether it comes out on top against the Ford Coyote or not, LME’s high-revving, small-cube LT is already a testament to what’s possible when you combine deep experience with a willingness to try something new.

Horsepower Wars would like to thanks its sponsors for making this possible including Summit Racing, Holley (Holley EFI, Simpson, etc), Manley Performance, Diamond Racing Pistons, COMP Cams, Moroso Performance Products, Automotive Racing Products (ARP), Cometic Gaskets, AMSOIL, Vibrant Performance, HPT Turbochargers, ICT Billet, ATI Performance, Meziere Enterprises, AFCO Racing, Optima Batteries, Old World Industries/Peak, Strange Engineering, SPAL, Auto Metal Direct, and Wiles Driveshaft.

Late Model Engines’ Bryan Neelen pulled everything out of his bag of tricks to maximize power in this tiny but mighty 5.3L LT.