You are here
Home > LATEST STORIES > Street Beast—Inside the 4,500-horsepower SMX engine that dominates Drag Week and cruises on ice cream runs

Street Beast—Inside the 4,500-horsepower SMX engine that dominates Drag Week and cruises on ice cream runs



Written by Jason Reiss

Photography courtesy of Steve Morris Engines

The origins of this story stretch back nearly five years, as longtime engine builder Steve Morris of Steve Morris Engines was working with his customer, longtime Hot Rod Drag Week competitor extraordinaire, Tom Bailey. The goal was to develop an engine package that could withstand the rigors of Drag Week duty, which are quite possibly the most demanding in motorsports—especially when you’re trying to race what amounts to a street-going Pro Mod without the benefit of a fully equipped trailer stocked with spare engines and transmissions.

Enter the SMX. Designed completely in-house at Steve Morris Engines to offer the best of both worlds, it has the street-going cooling ability found in a water-jacketed engine that’s required to see around 1,000 miles over Drag Week. Just as important is its incredibly robust construction, which is necessary to withstand more than 4,000 horsepower and 5-second quarter-mile elapsed times during the stops at the drag strips each day.

“Three years ago, I started thinking about it really hard and started working on all of the CAD and design work. I wanted to have a bulletproof, proven combination with readily available parts, instead of building the one-off deal. I had already been down all the roads of the one-off engines. If you run into problems and some small part breaks, you must be able to fix it right now and have all the parts available at the track,” says Morris.

In these early versions of the cylinder heads (left), we can see the exposed water jackets and plate retention holes on the top side of the billets, while the pair of heads on the right showcase the dry decks and external water passages on the outside of the head underneath the exhaust ports.

These fundamentals drove Morris’ efforts during the creation process for the SMX. Drag Week’s main requirement is that you need to be able to drive the car over those long distances between tracks in typical 90-plus-degree heat and stop-and-go traffic while pulling a 2,500-pound trailer filled with spare parts and other necessities too.

After winning three Drag Week overall championships and being the first car to run in the 6s at every track in 2013, Morris and Bailey battled parts failure of some sort over the next few years while chasing the 5-second barrier. It became evident that a better platform was needed. However, there was nothing available that was purpose-built for the type of abuse Drag Week heaps upon an engine platform.

Many years of testing with Bailey on Drag Week—as the Michigan racer chased the first 5-second run in competition—gave Morris a leg up on determining failure points for the engine design in this type of application. The nonstop thrashing on the car at the track, then sometimes 200-mile trips between tracks, often late at night, showed him which components couldn’t take the abuse of thousands of horsepower and still maintain reliability.

The intake side of the billet cylinder head offers up the water passages underneath the ports, along with O-ring port gaskets.

After a year and a half of working through the engine’s development stages, it’s here, it’s ready, and it can handle 4,500 horsepower while remaining docile enough to take for a ride to grab ice cream.

Bailey used the first SMX to run Drag Week in 2019, nailed down the first 5-second competition pass with a 5.99 elapsed time on the very last run of the week, and became the first and only Drag Week competitor to crack the 250-mph barrier on that event-ending blast. Bailey then ran it at the US Street Nationals at the beginning of 2020 and cracked off a 5.77 at 260 mph at 2,940 pounds—then blew up the internet with a video of the car pulling out of the track’s gates to hit McDonald’s for some race-day grub.

Additionally, he led the NMCA’s True Street field on its 30-mile cruise at the 2020 season-opening Bradenton event before running in the NMCA’s Pro Mod class. This engine is no joke—it performs the way Steve Morris designed it to do, by producing enormous power that’s genuinely streetable and durable.

Here, we see the inside of the lifter valley, where the water jackets are closed off with the welded-in plates. SME’s team is full of artisans who turn these blocks into complete works of art. Note that when you purchase one of these packages from SME, they can deliver it with the correct lifter bore diameter for your application, from .904-inch on up. Morris recommends purchasing everything through SME, as it’s easiest for him to provide support when he knows every piece inside the engine.

What Sets The SMX Apart?

First and foremost to note is the water-jacket configuration, which allows for a massive amount of water in both the block and cylinder head. Everything designed for a 481-X—cranks, rods, pistons, camshafts, lifters, and even rocker arm systems—can transfer right on over, as the SMX is designed to interchange with these components.

“The SMX engine is built to run for hours at a time, not seconds,” says Morris. “This is not built for just cooling down between rounds.”

The block and cylinder head combination must be purchased from SME as the upper head stud location was moved to accommodate the water jacket locations, and Morris is building an inventory of all engine parts to satisfy those immediate repairs or builds.

Looking at the block from the underside, we see the splayed billet main caps on the three center mains, along with the exposed top-to-bottom water jacket areas around the cylinders, on the side of the block.

Morris decided to use a dry-deck surface, which provides rigidity at the top of the sleeve area and provides the added benefit of ensuring head gasket retention under high boost values. In the block, water enters at the front of block and feeds to the rear where it crosses over and enters the lifter area. On the inside of the block, the water jacket locations are machined into place, then CNC-machined plates are welded into the block to close them up and allow the water to flow around the cylinders. They then come back out the front of the block through a large port.

The block holds one gallon of water, and the heads hold half a gallon. According to Morris, the SMX is about 25 pounds heavier than the traditional solid 481-X block, and about 33 pounds heavier when full of water. The extra weight is not insignificant, but is also not excessive, especially when you consider the additional material in critical locations. The SMX is not a wet sleeve block; it is dry, uses the same sleeves, and retains identical block thickness around the sleeves as what you would find in the 481-X.

Morris engineered an upgrade to the bottom end of the engine by developing splayed main caps rather than using the cross-bolted caps of the standard 481-X unit.

“We keep the Y pan rail so you can use the regular 481-X oil pan, but I prefer the splayed cap because I believe the cross-bolts only hold your oil pan rail together and don’t really do anything strength-wise. This design spreads the load down into the main webbing,” he explains.

Machined-in oil drain-back holes reside at the bottom of the block; one at the front, one at the rear, and can be used to drain the cylinder heads, and there is another port that can be used as a turbocharger drain. These holes enter the block right above the oil pan and simplify plumbing.

Another view shows the side and the underside of the block. Here we can see the monstrous front and rear oil drain-back holes located just above the pan rails, along with the center holes, which Morris says can be used for turbo drains into the pan.

Induction Specifics

SME designed the billet heads to accept all the valvetrain components from the Stage IV 481-X head, and his design uses a 2.450-inch intake valve along with a 1.920-inch exhaust valve. Morris worked with Manton on a new steel rocker system, proven on Drag Week in 2019.

The block will accept a splined or traditional keyed crankshaft snout.

The top head bolts we mentioned previously are accessed through plugs in the roof of the intake port. Once the plug is removed, the head bolt can be installed, and then the plug closes off the hole. Most importantly, the heads still come off without removing the intake, fuel system components, or electronics typically on the manifold.

“Instead of using the small 3/8-inch stud that used to be on the side of the intake port—but interfered with my water jacket—now we just go through the center of the port and down through the port into the block with a 1/2-inch stud,” says Morris.

Here, we can see the water passage exits in the front of the block at the outside of the timing cover. This design is ingenious, and as we’ve seen with Bailey’s program, extremely successful.
Morris worked closely with the folks at Manton to develop a bolt-in shaft-mount valvetrain system for the SMX. These are kept on the shelf at SME to make the buying process easy.
Visible are the block’s water jacket cover plate, and a view of the cylinder head’s water entry points from the front. Morris says the water enters in the lower port on the head to cool the exhaust ports first, then makes its way over the top of the head to the intake side, then exits through the hole at the upper front of the head. Also visible: Shop dog.

The real feat of engineering shows up in the water jacketing in the cylinder heads, which are machined from the same billet aluminum material as the block. Each passage had to be designed into the head in such a manner that they could be machined out using traditional tooling without compromising strength and durability—no small feat in an engine that can see north of 70 pounds of boost pressure.

“Water flows in from the outside, comes up around underneath the exhaust port, flows up by the exhaust port and spark plug, up to the top of the cylinder head, between the valves, then comes down on the inside of the cylinder head. This is maximum cooling. I’ve done a lot of stuff trying to figure out how to keep these things alive, stay cool, and run on the street at these horsepower levels,” says Morris.

Front view of an assembled short-block. SME keeps all of the components in stock to build an SMX, from the block, heads, intakes, covers, drives, valvetrain, and more.
Here is an assembled long-block, complete with intake manifold on top. Note the extra pair of injector rails underneath the plenum.

Additionally, SME also manufactures an intake manifold explicitly designed for use on the SMX engine. It can be configured with up to three injector locations per port to suit the customer’s application. For example, in a Drag Week application, the engine might require using a pair of large injectors during racing activity, while the third location could be used with a large-capacity supplemental fuel system with smaller injectors and a pump gas tune to run the car from track to track. Morris uses a dual-fuel system in Bailey’s car, as it races on methanol, but drives for hours at a time on regular old 93-octane pump fuel.

The SMX is designed for use with combinations other than a pair of turbos as well. If you have a craving for a screw blower, ProCharger, Vortech, or even naturally aspirated, Morris can supply you with an SMX so-equipped.

Wrapping Up

Put simply, the SMX is bad to the bone. Steve Morris has done all of the necessary engineering to ensure its success, and all of the required testing to ensure the platform is durable while retaining the ability to make massive power. Bailey’s performances deep into the 5s in Pro Mod competition and tickling the 5-second milestone after 800 miles of Drag Week proves out its capabilities.

With current options of 525, 540, and 572 cubic inches, we believe that it’s only a matter of time before the SMX is widely adopted in serious streetcar circles, powerboats, off-road applications, and even potentially in a supercar application. Morris appears to have thought of everything during the design process.


Steve Morris Engines

231 | 747 | 7520