LSX Drag Radial Engine Build Part 2: Capping it Off


In our last update, we left off with the first of a two-part engine build-up as we walked through the short-block assembly of an LS-based powerplant destined for small-tire, heads-up drag racing a whole lot of supercharged boost. In that story, we followed Mike Consolo and the gang at Quarter Mile Performance (QMP) as they stuffed some bling in our 2,000-plus horsepower-capable LS Next block from Dart Machinery. And when we say “bling,” we mean it. Winberg Crankshafts supplied us with a showpiece of a crank, while GRP set us up with extra beefy billet aluminum rods that were topped off by a set of sharp-looking flat top slugs from Ross Pistons. 


Mike Consolo from QMP Racing Engines torquing down the heads on our Mast Mozez LSX long block. QMP, located in Southern california, fields some fast hardware including leaf spring legend Al Jimenez and the 8.5 thumper, Ryan “Toaster” Jones.

As we committed the short-block build to the history books, we turned our attention toward the top half of the engine. Our first step was to solicit the advice of top-performing manufacturers like Mast Motorsports, Comp Cams, ARP, and several others. To meet our goal, we needed a long-block that would match the high standards set forth in the short-block, and these companies were up to the challenge.

It started with Dart’s LS Next, a platform designed for ample boost, as we talked to the legendary Dick Maskin to kick our build off right. Then we moved on to Mast Motorsports to discuss its LSX Mozez offering by covering The Anatomy Of A Full Race Radial 275 Induction System.

Previously, we’ve discussed our Induction Priorities by covering Mast Motorsport’s high-flowing top end Mozez package. As a reminder, the setup came from Mast with two bare Mozez cylinder heads and a matching tunnel ram intake.

Dick Maskin at Dart got us started off right with a solid block to load our parts into. (Left) The front face of Dart's LS Next. (Center) A shot of the block's rearend. (Right) The underside of the LS Next, showing the unique pairing of Gen I main caps on an LS-based block.

From there, it was on us to fill the heads with valvetrain components and top the manifold appropriately. We went about this task by working with Chris Padgett from Comp Cams for its top-of-the-line lifters, springs, and retainers. Ferrea Racing Components helped us pick the 2.250-inch intake and 1.600-inch exhaust valves and, as you may recall from Rocking the Valves, T&D Machine pulled together a set of high-endurance steel rockers for our build.

(Left) The massive Mast Mozez small-block cylinder heads accompanied by a shot (right) of the equally massive Mast cast tunnel ram.

To dry deck the heads, we were presented with several options: (1) run a head gasket without water passages. (2) weld the deck, or (3) machine precisely-sized aluminum plugs that are press-fit into the head water passages. Even though it was more costly and difficult, we opted for option three, as it was the least destructive for the cylinder head. In addition to filling the block and “dry decking” the heads, we also opted to order the head gaskets without water passages.

How big are the ports on our Mast cast tunnel ram? Yeh... That big.

How big are the ports on our Mast cast tunnel ram? Yeh… That big.

Before assembling the heads, QMP had to button up a decision made earlier in the build. In our first story covering the short-block build we explained how the block was filled, resulting in a configuration traditionally known as a “dry deck.” As Mike At QMP indicated, “In an application like this, it’s best to fill the block, plug the heads, and run water through the heads. Doing so eliminates compounding issues with water seepage if you push it too hard and lift the heads.“

About the ARP head studs, Mike mentioned, “With this setup we got lucky, the head studs are relatively short which dramatically increases their durability, add to that the increase in diameter to half-inch and I’m not worried” For head gaskets, we gave SCE Gaskets in Southern California a call and got a hold of Caleb Hunter. He had already heard about our project from our previous stories and knew we would need a custom gasket to plug water passages and accommodate the larger half-inch head studs. To play it safe, SCE provided a template that we could use to mark-up with stud sizes and water passage omissions.

 A close up of the deck of our Mast Mozez head. QMP cut small aluminum wedges and pressed them into the head to create a "dry deck" head. It's a costly but process but does not require welding that puts heat into the head.

A close up of the deck of our Mast Mozez head. QMP cut small aluminum wedges and pressed them into the head to create a “dry deck” head. It’s a costly but process but does not require welding that puts heat into the head.

After discussing the merits of multi-layer steel shim (MLS) gaskets versus copper, the result was a set of pure copper, 0.60-inch thick, 4.165-inch bore head gaskets to accommodate the o-ringed block and heads. For our build, we had determined that MLS gaskets, while extremely effective, were too unforgiving for our combination.

Once we had a completed short-block, head gaskets, and assembled the heads, we worked with ARP to source a top-of-the-line set of fasteners to pull it all together. In addition to larger head studs, we opted to measure and custom order most of the critical fasteners required for the build.

The short block with our Ross flat top pistons taking a peek at the ARP head studs. The studs are relatively short for the large head and we switched to a 1/2 inch stud, both of these factors helped increase strength.

The short-block with our Ross flat top pistons taking a peek at the ARP head studs. The studs are relatively short for the large head and we switched to a half-inch stud, both of these factors helped increase strength.

To supplement our custom order, ARP supplied us with their 534-9705 accessory kit for the intake manifold, rear cover, and other components.

Our cast Mozez manifold is complimented by Moran Billet Atomizer 235lb injectors. Before assembly, we have the manifold sent to Bryan Neelen at LME racing engines for a 100 percent billet top and modification for our 123 mm Wilson Manifolds throttle body.

After locking down the heads, QMP completed the tunnel ram installation. We ran into a snag, as we originally ordered a manifold intended for shorter deck height than we ended up with. However, the guys at QMP easily navigated this issue by cutting two 1/4-inch spacers that they then attached to the manifold to fill the gaps created by the heightened deck. As an added bonus, we were able to retain manifold to head O-ring feature by O-ringing and then pinning the new spacer plates in place.

ARP provided all of the hardware needed for this extreme build.

ARP provided all of the hardware needed for this extreme build.

Rounding Off The Edges

One of the biggest hurdles in putting together a race engine is making it “look” like an engine.

In other words, you need to get the rotating assembly installed and torqued to specification, install and degree the camshaft, the valve-train needs to be put in place, and then the heads and manifold installed to complete the package. With the long-block milestone behind us, QMP wrapped the engine in plastic and waived goodbye as the big brown truck hit Interstate 5 and made its way north to its final home.

Now the fun really begins.

After delivery, there were several steps that needed to take place before the engine could be dropped between the freshly-painted frame rails of our Chassisworks’ tubular front end. First, we needed a flexplate. After weighing the options, we decided not to cheap out, and went with Meziere’s new billet flexplate. We opted for the FP319, which has 168 teeth, weighs seven pounds, carries an SFI 29.2 rating, and is said to keep cool to 12,000 rpm (we only plan to spin the engine to 9,000 rpm).

“As with all of our billet Flexplates, the FP319 is constructed from 4340, 14-inch round billet bar stock, which is 20-feet long and weighs nearly 20,000 pounds, said Don Meziere. “It’s definitely not the easiest way to start, but we really believe it is the best. By using round bar, the grain structure running through the plate is more consistent. This round billet is sliced into thin pieces and the CNC machining processes begin. To ensure flatness, we use three turning operations and make sure the axial runout is less than .003 inches.”

(Left) The LS 'short-nosed' crankshaft snout with two 90-degree, offset 3/16-inch keyways to prevent the extreme forces of the supercharger from rolling the balancer hub over the woodruff key. (Center and right) A look at our ATI balancer. The balancer comes as a two-piece unit. First, a steel hub is used to fit the assembly onto the crank with the proper spacing. Our hub has the matching groove for our dual 3/16-inch keys. Second, the balancer shell is fitted to the hub with ATI hardware. In our case, the shell has an option to include magnets that will send crank location data to the Holley EFI unit.

With the flexplate installed, we were able slide our Neal Chance NSX torque converter into the two-speed TH-400 transmission, bolt the bell housing to the LS Next, and drop the entire assembly into the Camaro. Alas, the Camaro has a new heart.

Getting Blown


It’s starting to look like something. Vortech’s XB supercharger mounted to Chassisworks’ CDS unit, mounted to our LSX. The CDS places the Vortech unit in front of the engine and low enough to add an inlet through the front end air dam. Once completed, the supercharger will be plumbed with it’s own oiling system and spit air into an air to water intercooler fabricated by Chiseled Performance.

Once set in the car, we moved to the opposite end of the engine to prepare for the Vortech-inspired boost. That started with a call to our buddy Chris Alston Jr. at Chassisworks to figure out what we would need to modify our Gen I Component Drive System (CDS) to the LS platform. To our surprise, the swap consisted only of changing two minor pieces of the system.

These builds are always tough the first time through. Now that we’ve gone through it once, everything will fall together in future teardown. – Mike Consolo

Beyond changing the billet block adapters, everything else, including the stands and gear case, remained the same. Alston Jr. warned us that this may not always be the case and that new measurements should always be supplied when ordering, but in this case, with our LS balancer placement, we lucked out. The CDS system provided us with a solid platform for mounting Vortech’s hardware. Which Vortech we’ll be running is still a secret, but we’ll be detailing the specifics of the supercharger in a future story.

We looked at several gear drive units for our supercharger before we settled on the Chassisworks CDS unit. After comparing what was on the market, it was a no brainer. Here are some of the features we liked:

  • The legs are all indexed for a press fit, meaning they locate and hold together even without the bolts (though you need the bolts). This means that the drive doesn’t have the ability to wobble or walk even if the bolts aren’t super tight.
  • Uses “pick up at the corner speed parts store” Winters quick-change gear sets that you can buy from Summit for $65. This is much cheaper than competing units that charge as much as $300 for a single set of gears.
  • Has a built in timing pointer (not clearance for one, but one actually built-in), built-in crank trigger pick-up, and oil level indicator window.
  • Uses a stainless billet hub (not aluminum), that doesn’t deflect or shear, along with bushings that last longer than the 10 to 12 passes expected from some competitor units.
  • Has both a crank speed drive and a blower speed drive that mount using a standard one-inch keyed mandrel.
  • The mandrels can also be used with Chassisworks drive extensions to drive accessories like fuel pumps, oil pumps and vacuum pumps.
  • Comes with the provisions built in to change motor platforms while using the same drive unit. Our unit required switching of block adapters to use the same drive assembly.
  • Comes with the provisions built in to change blower platforms while using the same drive unit. We’ve used the same unit for six different superchargers from ProCharger and Vortech.

Mounting the Chassisworks CDS system is relatively strait forward. (Left and Center) Block adapter mount to the block and accept stands that mount the gear case. (Right) The gear case is mounted and accepts stands that mount the supercharger. We've now used the same CDS unit on two different engines and with 6 different superchargers.

Valve Covers And Pan

The Mast Mozez head design utilizes a SB2.2 valve cover bolt pattern but with a twist. The rockers on the head are located more rearward than in a traditional SB2.2 and, as a result, tend to interfere with the top valve cover rail if a traditional SB2.2 valve cover is used. Williams Performance is able to avoid this problem by fully manufacturing purpose-built valve covers rather than recycling a SB2.2 design.

Valve covers from Williams Performance fitted to the heads of our Mozez heads. They are fully fabricated with H-14 aluminum sheet and a T6 billet rail.

They’re constructed using 0.090-inch 3003 H-14 aluminum, and seal to the head with an O-ring and a 3/8-inch 6061 T6 billet rail. One of the significant differences between a typical LS block and a LS Next is the main cap, and by extension, the oil pan design. Traditional LS blocks are skirted, while Dart removed the skit and opted for traditional splayed main caps on the LS Next.

Williams Performance also constructed our fully fabricated aluminum dry sump oil pan. It features a full passenger side kickoff, four scavenger pickups, and provisions for a full-size starter.

Dart worked with Moroso to develop pan rails that would adapt a typical LS oil pan to a LS Next. However, Dick Maskin and the Dart crew had the foresight to mimic the pan rail dimensions of its popular Iron Eagle Gen I block. As a result, the crew at Williams already knew what was needed when we requested a four-stage oil pan for the project. The pan came with a full kickout, provisions for a passenger side starter, and -12 scavenger filter fittings to protect our Peterson R4 dry sump oil pump.

MLS Or Copper?

“Copper head gaskets act like a fuse, they’ll seal, but if you get the tune-up wrong, they give. The MLS setups seal really well but don’t have any give. When they go, they tend to take something with them.” – Caleb Hunter.

The MLS or, multiple layer steel shim, gasket is just as it’s name sounds. It incorporates several layers of thin steel shims that are sandwiched on top of each other and then held together with rivets. The gaskets require very smooth deck surfaces and are not recommended for use with wire O-rings. However, because of the superior sealing characteristics, they do not need them. Many builders opt for MLS gaskets because they hold their seal when subjected to extreme cylinder pressures. This strength is also their weakness. Because MLS gaskets seal so well and are made of steel, they resist failures and redirect the damaging flame front of a missed tune-up into the head or cylinder block. This results in damage to parts that are significantly more costly and harder to repair than a burned head gasket.

MLS gaskets (right) compared to the copper and O-ring setup we'll be using. Copper gaskets act as a fuse and fail before mortally damaging more expensive parts like the heads and block.

Copper is a much softer material and will fail well before burning a hole in expensive heads. To offset some of the strength losses when going to copper, most builders will compliment a copper head gasket with a steel wire O-ring in the head deck and block surface. The wire forms a ridge in the malleable gasket material that increases the gaskets resistance allow pressure blow by in extreme cylinder pressure situations. No gasket material is perfect and each builder will have his preference. In our case, we opted for copper, O-rings, and a dry deck over risking damage to the block and heads should we decide to lean on the tune-up.

Igniting It

One of the critical supporting components of this build is the ignition system. In the past we had used MSD Performance ignition components. Specifically, we had a tested a 7531 Digital 7 unit coupled with a billet crank trigger distributor and HVC II high output coil. This combination provided us with reliable spark that was adjustable via laptop for killing the power to get off the line at marginal tracks.

When MSD upped the ante with the Powergrid system, we were one of the first onboard, by marrying the Grid brain to our old 7531, which we eventually phased out for the Grid spark box. For our LSX build, we increased the compression, went more aggressive with the cam profile, and expect to play around with several high boost-producing compressors.

MSD Ignition is the standard for lighting off spark. The MSD components we will be using include the HVC II coil, MSD’s proven 8-Plus CD ignition box, MSD’s Grid spark controller, the Grid ignition which in our case will be replaced by the 8-Plus box and its camshaft driven distributor. The cam driven distributor mounts to the front of the engine (shown right) and is driven by a cog belt and pulley that is attached to the cam sprocket.

In response, Joe Pando at MSD told us that we had to step up our spark potential. As a result, we re-engineered to entire system starting with a state-of-the-art, cam-driven distributor that will take instructions from a hybrid of capacitive discharge (CD) spark signals from the MSD 8-Plus and digital instructions from our 7730 Grid brain.

The intersection of these ignitions gives us two things: first, we’re able to bump spark output by 125 millijoules (mJ), from 220 mJ to 345 mJ, which is huge. Second, we’re able to retain the smart features of our laptop-tunable Grid system. These features, together, have been proven to be an effective combination for lighting off the air and fuel in a consistent manner, while controlling timing down to the decimal for precise power management on our tire-limited Camaro.

The engine build is now complete and sitting between the framerails of our 1968 drag radial Camaro.

With a great hand from Mike and the guys at QMP, we’re seeing some light at the end of the tunnel. Stay tuned as we bring you a closer look at our oiling system, the supercharger, and our on track testing with our Holley EFI setup.

Article Sources

About the author

DJ Reid

DJ has been involved in door slammer drag racing for more than a decade and a half. As a Silicon Valley insider, his interests and expertise are focused on the software technology that powers fuel injection, data acquisition and ignition control. His race team is based in Northern California but travels from coast to coast. DJ’s current operation revolves around a leaf sprung, blown and LS-inspired 1968 Camaro that he uses as a test bed for emerging technologies with various manufacturers. He is a vocal member of the racing community and uses his industry relationships to share findings and new innovations with that community.
Read My Articles

Drag Racing in your Inbox.

Build your own custom newsletter with the content you love from Dragzine, directly to your inbox, absolutely FREE!

Free WordPress Themes

We will safeguard your e-mail and only send content you request.