LS Turbo Power: Building Project Red Dragon’s New Short Block

Project Red Dragon is transforming into a new kind of monster…unfortunately, like so many transformations that happen there is some pain involved. Our plans for the fourth-generation Pontiac Firebird have had to change many times due to COVID, parts availability, project changes, and even parts failures. We’re getting closer to putting the car back together and in this article, we’re going to cover the Red Dragon’s new engine combination.

Problems And Solutions

The plan for Project Red Dragon’s conversion to boost seemed solid and well thought out when we started the process. Little did we know, however, that a global pandemic was going to arrive on our shores and smash every timeline we had into tiny bits.

The new GM Performance block helped eliminate the issues we were having finding a starting point for our engine build.

We pushed through the issues COVID-19 presented, got parts, and we were ready to start buttoning up the solid used short block we purchased until disaster struck: one of the head studs broke off inside the block. At first we thought we could just extract the broken piece, but then we realized the block was compromised. Unfazed, we scored a junkyard block to use with our stock LS1 crank, and sourced the remainder of the rotating assembly parts to get started on the “new” engine.

Well, we shipped the block, crank, pistons, rods, 317 cylinder heads, and other parts to our engine builder, Jimmy Bowling at All-In Racing Engines, to start the build…or so we thought. Soon, Jimmy informed us the block we found was thrashed, the heads would need new valves, and the crank wasn’t useable. We were at an impasse with the project, so say the least.

We decided it was time to stop playing around and purchased a new 6.0-liter GM Performance block from Summit Racing Equipment and had Lunati send us a new crank. Our 370 cubic-inch LS engine went from being a junkyard hero to a boosted cage fighter, and we’re excited to see what it will do.

Solid Rotating Assembly

Since our stock crankshaft wasn’t going to be up to the task of handling a lot of boost, we had to go another route. For that we turned to Lunati and one of its Voodoo crankshafts for the LS engine. Since we’re trying to keep things within a reasonable budget range, the Voodoo crank is perfect with its street price and strength.

The Voodoo LS crank is made from a 4340 no-twist forging, which makes the crank very durable and strong. Lunati added lightening holes to the rod journals to decrease the amount of inertia the crank generates so it can accelerate faster. The Voodoo crank goes through a nitride heat-treating process and each journal is micropolished.

The stock-stroke Lunati Voodoo crankshaft is a great budget-friendly upgrade for a boosted LS build.

A stock LS crankshaft can live in the 1,000 horsepower range, but you’re going to be walking a fine line with how long it could last at that level. Will Vance from Lunati explains why upgrading to a Voodoo crank for a build like this makes perfect sense.

“This crank provides the best bang for your buck since it allows you to add horsepower as your boosted application progresses. The forging is rated for 1,000 horsepower and we’ve seen people make 1,600 horsepower with this crank. You can’t do that with a stock crank, so it makes sense to go with a strong and affordable crank like this one.”

Bowling has put together his fair share of engines that are fed a healthy dose of boost, and he chimes in with his thoughts on why you need a good crank in a build like this.

“A good crank is so important if you want to make a lot of reliable horsepower with boost. The stock LS crank is a good piece, but stepping up to an aftermarket crank is the best course of action if you want something that’s going to last. This Lunati crank is a great option for a street car that’s going to make 1,000 horsepower to the tire.”

MAHLE supplied a full set of bearings for our build that are designed for a boosted application.

A good rotating assembly isn’t going to last long or perform how it should if you don’t use good bearings. Our plan is to throw a lot of boost and horsepower at this engine, so we need bearings that can deal with the heavier loads and torsional movements that will be laid on them. The bearings need to have an increased amount of crush so they don’t move around. This also goes with the load-carrying ability of the bearings to prevent seizure.

We decided to use a full set of MAHLE performance bearings that have a cast copper lead substrate. According to MAHLE, these bearings have an increased load-carrying capacity versus bearings that have gone through a sintered process.

Dan Begle from MAHLE discusses the importance of quality bearings and the benefits they provide.

“Usually a bearing doesn’t achieve higher horsepower unless you’re optimizing the oil flow on extremely refined engines. A quality bearing will add a large amount of reliability to the engine. Using a non-performance bearing can result in overlay fatigue, bearing movement, or other issues possibly resulting in an early failure.”

Increased cylinder pressure, heat, and engine component movement have a negative effect on stock gaskets. – Dan Begle, MAHLE

Gaskets are another item that might be tempting to try to save money on during a build, but that’s never a great idea. If you want to avoid some simple problems and performance issues it’s best to go with good aftermarket gaskets that can deal with abuse…especially if you’re trying to generate a lot of boosted horsepower.

We’ve seen first-hand the epic carnage that can occur when a gasket fails at the track, so we called on MAHLE once again to help us select the best gaskets for our application.

“Increased cylinder pressure, heat, and engine component movement have a negative effect on stock gaskets,” Begle explains. “Adding a power-adder increases all of the above issues, and can cause a sealing concern if you’re not using an upgraded performance gasket. Typically, a power adder will cause more deformation, particularly to the cylinder head, which will affect its clamp load, causing sealing issues. It is important to increase the combustion seal thickness, as higher cylinder pressure can allow more cylinder head movement.”

Lunati designed the Boosted X-Beam rods to be the ideal forced-induction connecting rod for an LS engine. They combine the strength of an I-beam rod, while not being too heavy.

The foundation for our stout rotating assembly was laid with the Voodoo crank — it was time to move on to the connecting rods, and we selected another product from Lunati to check that box. The Lunati Boosted X-Beam connecting rods could be the most trick off-the-shelf rods you can get for a boosted LS application. Lunati found a way to combine the best features of a lightweight H-beam rod used for N/A applications, and the strength of an I-beam rod used in boosted engines into one part.

Lunati claims the Boosted X-Beam rods are good for up to 1,700 horsepower and 9,000 RPM in a boosted application — this is more than enough for our build. The rods are made from a 4340 material that has been through a stress-relief process, shot-peened, and magnafluxed so they can deal with high-horsepower abuse. Each set of rods is weight-matched before they ship, and they use ARP 2000 7/16-inch rod bolts.

Lunati’s Vance explains why these rods are perfect for any boosted LS build.

“These Boosted X-Beam rods provide a great cost-versus strength value. You can grow into these rods as you crank up the horsepower, or you can use them right away in a build that’s making a lot of steam. They have a reduced rotating weight, but still have plenty of strength for a boosted build. We also made sure these rods have close tolerances and use stringent quality control measures to make sure they will last in the most extreme engines.”

MAHLE's PowerPak LS pistons are a drop-in solution for a 370 cubic-inch engine and shouldn't have any issue dealing with boost.

Forged pistons were the final item we needed to select for Project Red Dragon’s new 370 cubic-inch engine. A set of 2618 forged PowerPak pistons from MAHLE Motorsports fit the bill for our application. The 4.030-inch bore pistons weigh 441 grams each, and with the 70cc combustion chambers of the 317 heads, give us a 10.2:1 compression ratio. The PowerPak pistons come with a full set of rings and use a hard anodized top ring groove that works great for boost builds like ours.

Forged pistons like the MAHLE PowerPak slugs we’re using give a boosted engine more strength and reliability. Joe Maylish from MAHLE shares why the 2618 material is better than 4130 for a build like ours.

“The 4032 has a higher silicon content, low expansion rate, and moderate strength, can be found in passenger cars, street/strip applications, and it can be used with moderate power-adders. The 4032 also has a quieter piston operation. The 2618 will be found mostly in high-horsepower N/A, forced induction, and nitrous applications, and has a lower silicon content, a higher expansion rate, and increased strength, which allows it to function in harsh conditions. It can have the potential for more piston noise at cold start, but it is also more forgiving.”

Bowling adds his thoughts about the rods and pistons that were selected for this build.

“This rod and piston package should hold up well for this application. The Lunati rods are more than strong enough for this power level and they aren’t too heavy. MAHLE did a great job with the piston design, and using 2618 for the material adds durability. Everything went together as expected and that’s always a good thing.”

A quality rotating assembly isn’t worth anything if you don’t use the proper fasteners to hold everything together. We decided to fill our 370 cubic-inch LS with fasteners from ARP, including a main stud kit and head studs to go with our ARP rod bolts. The main stud kit is great for a turbo application because it ensures the main caps won’t try to move around thanks to the 8740 heat-treated chromoly steel they’re made from. The factory hardware is really only designed for factory-level horsepower, so if you’re going to crank up the boost as we plan to it only makes sense to use an aftermarket main stud kit.

Having a full set of ARP fasteners is a must for a boosted build like this one. The main caps will be kept in place by a set of studs along with the cylinder heads.

The heads also need to be addressed with good fasteners for a boosted build. You don’t want to deal with a head trying to lift off the block creating sealing issues or having other damage occur. The ARP Pro Series head stud kits are perfect because they not only provide more clamping power, they’re also reusable in case you need to do engine maintenance or upgrades.

Chris Raschke from ARP provides some hints about how to get the most out of your fasteners.

“You need to follow the instructions included in the kit…this is very important. That being said, the assembler or builder should always check the line bore for size, straightness, and roundness. You’ll also want to make sure the threads in the block are clean before you begin assembly. The fasteners should also have our Ultra-Torque fastener lubricant applied to them to ensure a consistent torque preload happens.”

Top End Fun

Our original plan for Project Red Dragon was to freshen up the heads and valvetrain with turbo-friendly parts, but as we outlined earlier, Murphy’s Law came down on us hard. Thankfully, we were still able to use all of the valvetrain goodies COMP Cams sent us. We worked with COMP to spec out a killer boosted valvetrain that would help our engine make 1,000 horsepower, but also have plenty of durability, too.

Camshafts for turbo LS applications need to have plenty of stability at higher engine speeds. A turbo LS engine can be fed plenty of air well past 7,000 RPM, and you need to keep that in mind when evaluating what camshaft you select. It’s easy to take a valvetrain well past its safe point with a turbo engine, so you need to select parts that can deal with higher RPM levels.

Using any old camshaft isn’t the best course of action for a turbo LS build. You want to select a turbo-specific camshaft that will help the engine breathe properly.

Billy Godbold is one of the valvetrain experts at COMP Cams and he’s built some nasty LS engines in his time. Godbold explains why you want to be mindful of keeping your turbo camshaft stable in an LS engine.

“The camshaft needs to be far more stable for a turbo engine in the region between where you’re trying to make peak power, and where you want to set the rev limiter than in a N/A application, because this is generally the area you want to operate in more for best performance. Many of the ‘trick of the week’ camshafts are pretty stable from 4000-6000 RPM, but start to have major issues as low as 6200 RPM. When you’re approaching four-digit power numbers, any stability issues in this region can leave you with a pile of very expensive broken parts, and no idea what happened.”

Horsepower may seem easy to make with a turbo, but if you don’t have the right camshaft you’re going to leave a lot on the table. A cam that’s optimized for a turbo application is going to help the engine breathe better and make the most usable horsepower. You don’t want to go out and grab the biggest camshaft on the market…you need to get the right one for your specific engine.

“The dense air of a turbo, especially when intercooled, make the cylinder head ‘seem’ a whole lot better than you might normally believe. When you’re running 14-pounds of boost, depending on the temperature, the air is twice as dense as normal air. This is like if you put a better head on a naturally-aspirated engine — once you’re able to move more air mass, the cam timing can be much shorter for the same RPM. Often we will see 20-degrees less duration on a turbo application than you would see in the same engine at the same RPM without the turbos, or even a bigger change with high back-pressure, where you have to be very careful with overlap,” Godbold says.

When you’re approaching four-digit power numbers, any stability issues can leave you with a pile of very expensive broken parts, and no idea what happened. – Billy Godbold, COMP Cams

The Red Dragon’s 370 cubic-inch LS engine is going to see plenty of RPM, so we needed to upgrade the entire valvetrain of the engine. COMP Cams’ BSR high-lift shaft rocker system is a trick part that bolts right onto stock LS heads, and it ties all of the rocker arms together so they’re extra stiff. The BSR rocker arms also have better geometry, and use a solid tri-metal bushing, so that removes a failure point of the OEM rocker arms.

The last thing you want during a pass is the valvetrain to become unhappy. COMP's BSR rocker arms add plenty of strength and will prevent any flexing issues.

“Warren Johnson recently said, ‘you can’t tune it up if you’ve blown it up’ — he wasn’t talking about turbo motors specifically, but the shoe fits. You can certainly make great power with a comparatively inexpensive engine, but back to the idea of a pile of broken parts, you cannot do that with a failed valve tip or broken rocker. The GM rocker body is awesome, but the factory bearing is suspect and the mounting can flex. The BSR system anchors the centers of the rocker arm, and adds the most robust tri-layer bushing that we have ever seen to a great rocker body,” Godbold states.

Valve springs are one of the most important parts of the valvetrain, and you don’t want to skimp on them. The camshaft kit we got from COMP included a set of upgraded valve springs that are matched to work with the cam we wanted to use. COMP runs its cam profiles on a Spintron machine to make sure the packages it sells are stable throughout the engine RPM range under boost.

Big cams require beefy springs and retainers. We got a full set of springs and retainers from COMP that are designed to work with our combination.

“You need to look for an engineered package or work with the camshaft manufacturer to find out what parts work well together. Loads and sizes are completely useless specs when it comes to valve springs. The cam profile and the valve spring are in a very intricate and intertwined dance. The cam profile has the lead part, and the valve spring has to follow along backward and in high heels. If these two are not great partners, disaster is right around the corner,” Godbold says.

Lifters aren’t a part you see from the outside of an engine, but that doesn’t mean they aren’t important. In a turbo application, the lifters are put under a lot of stress, especially by two-steps and boost controllers. A stock GM hydraulic lifter is a great part for most turbo engine builds, but since we’re pushing the limits of stock parts we opted to upgrade here, too. COMP’s short-travel hydraulic lifters are great because they’re designed for high-horsepower applications and have an enhanced bearing package. These lifters will be less likely to have bearing issues under a boosted loads.

Upgrading the pushrods and lifters was another requirement for our build.

Pushrods experience a lot of stress in a boosted engine, so we knew the stock GM parts wouldn’t cut it for our build. COMP includes its Magnum pushrods as a part of each cam kit to make sure you have something that can deal with the extra horsepower. The Magnum pushrods are made of C1020 high-carbon chromoly steel, have been heat-treated, and have a thick .080-inch wall.

Godbold explains why you need to upgrade pushrods for a build like this one.

“The pushrods experience over 3,000-pounds of inertial loads as the valve accelerates off the seat and then just before the valve closes as it stops the valve from crashing into the seat. These loads can actually exceed the buckling limit of the pushrod, but the pushrod experiences this so quickly that it does not have time to fail before the load is removed. All you have to do is look at a stock pushrod and think, ‘would I want to try to lift my car with that little tube?’ ”

Now that All-In Racing Engines is done with our 370-inch LS engine we can start putting everything together. Make sure you follow Project Red Dragon right here on Dragzine. We’re going to have the engine back in the car soon and will outline that process along with everything else we’re doing to get the move to boost finished up. Stay tuned!

Article Sources

About the author

Brian Wagner

Spending his childhood at different race tracks around Ohio with his family’s 1967 Nova, Brian developed a true love for drag racing. When Brian is not writing, you can find him at the track as a crew chief, doing freelance photography, or beating on his nitrous-fed 2000 Trans Am.
Read My Articles

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