Pony Wars: Forging The Camaro’s LT1 Engine For Boost

In the last installments of Horsepower Wars: Pony Wars, our 2017 Chevrolet Camaro SS and our 2017 Ford Mustang GT received more than $15,000 worth of modifications. Naturally with a $15,000 budget, some of that was bought up by way of boost (thanks to ProCharger). However, with big boost often comes the need for stronger engine internals, which is why we’ve decided to build a long-block for our LT1-powered Camaro SS.

We’re in need of a forged engine which will take upward of 15 psi or more of boost. And with the help of some of the biggest names in the industry supporting this long-block build, including – ARP Bolts, COMP Cams, L&R Engines, MAHLE Motorsports, SCAT Crankshafts, and Texas Speed and Performance – we were able to build a forged long-block that could handle our boost cravings with ease. In this segment, we dive into the details of our new forged long-block. We detail which components we chose, how they will be used and how they will effect the big picture when it comes to our Pony Wars endeavors.

The Bottom-End

Our factory 6.2-liter LT1 V8 and eight-speed 8L90E automatic transmission being removed.

The foundation of our engine build makes use of our factory LT1 block and cylinder heads, albeit they have been modified for our build. The Gen V 6.2-liter LT1 block has been massaged by L&R Engines. The process begins by L&R hot tanking the block, followed by a light power-hone. Since our LT1 V8 is lightly used with only a few thousand miles on it, Derek at L&R Engines says the block only required a light power-honing.

“Whether an engine has 0 miles or 500,000 miles, we hone every single block that enters our doors,” Derek enthused. “We do this to verify the piston-to-wall clearance is 100% accurate by creating new hatch marks. For this build, we only had to take about 1-2 tenths of an inch out to straighten all of the bores.”

Once the block was in good hands, L&R began stuffing it with all of our new components for the build. The build kicked off reassembling the factory oiling system components, followed by main (and connecting rod) bearings. The factory coated main bearings were brand-new so those were left untouched, while we did upgrade the rod bearings with Clevite H-series (PN CB663HN STD). L&R stocks these tri-metal TM-77 bearings, and they are pretty much all they use. The H-series was developed for NASCAR and have a “medium level” of eccentricity and a high crush factor. Perhaps its most relevant feature, though, is enlarged chamfers to clear the rolled fillets that GM generously furnishes on its factory LS and LT crankshafts. This combination lets you spin the engine worry-free.

For this build, we used 4340 forged H-beam connecting rods (PN 2-350-6125-2100) from SCAT. Since rods are not offered in the factory dimensions, we stuck with the familiar LS specs – 6.125-inch long and .927-inch pin bore.

These connecting rods come with 7/16-inch ARP 2000 rod bolts straight from SCAT, which means they are able to hold more horsepower than your typical off-the-shelf H-beam rod. Since we are reusing our factory forged LT1 crankshaft, these rods are perfect for our application, as they match the stock stroke (3.622-inches) and the forged pistons we selected (in length/pin bore).

Short-Block Continued

MAHLE Gen V LT1 forged pistons (PN 930228365) are tasked with compressing that fine mixture of fuel and air.

The MAHLE PowerPak pistons are comprised of 2618-grade forged aluminum and feature an inverted dome with valve reliefs cut into them. The 2618 alloy does not boast the temperature resistance of 4032 used in some PowerPak applications, however, it is much more tolerant of detonation. “All the GM LT PowerPak piston applications are supplied with hard anodized top ring grooves,” Trey McFarland at MAHLE told us. “Micro-welding of the top ring grooves, which reduces ring seal while increasing blow-by, is more common at lower output levels on direct injection applications due to the increase in cylinder temperatures and pressures these engines produce.”

“MAHLE’s slipper skirt forgings reduced mass design that positions more of the pistons mass in the crown area instead of below the ring belt reach operating temperature much quicker than parts produced with older design full round forgings. This greatly reduces the time the pistons are operating with additional clearance reducing both wear and noise. Through multiple R&D efforts with GM on LS/LT programs from OE to Corvette Racing and the COPO Camaro, MAHLE has developed LS/LT specific profile and ovality geometries that aid in performance, durability and noise reduction.”

We chose to stick with the factory bore (4.065-inches) as we wanted to keep the entire long-block build stock displacement and as close to stock compression ratio as possible (10.0:1 with our stock 60cc combustion chambers). MAHLE also offers a piston for 12.4:1 compression for E85, low boost, nitrous or naturally aspirated applications. Between the 15psi of boost and our normal diet of pump gas, 10:1 seemed like a much better plan.

The PowerPak includes its own unique ring pack, which L&R filed to .024 (top) and .026 (middle) ring gap for big boost.

Before final installation of our short-block took place, L&R computer balanced our rotating assembly within just grams of accuracy.

Concluding the short-block portion of the build is our camshaft from COMP Cams (PN 224-000-13).

The specs of our new Gen V LT1 camshaft boast big lift (.619-inch intake/.646-inch exhaust) and favorable duration (223/235 degrees at .050) with a Lobe Separation Angle of 114. This camshaft is made specifically for use without Active Fuel Management (aka DOD), and has Comp’s triangular fuel pump lobe that increases fuel flow through the mechanical pump by 32% with 7.5mm lobes.

“While the canted valve is new with this engine, the airflow characteristics are very close to something like LS7 flow with an LS3 cross section,” according to Billy Godbold, Valvetrain Engineering Group Manager at COMP Cams. “The same profiles that were developed with these engines in mind are great with the LT1 engine and head. The one difference in terms of cam specs would be that the higher velocity port does not require quite as much overlap to make the same (or more) power. The cores are quite unique with the swapped intake and exhaust valve location along with the added DI pump lobe, but the general profiles are very much in line with the LS7 and the durations are just a touch less.”

Head Games

With the short-block finished, L&R moved onto mounting the Gen V LT1 specific head gaskets in preparation for our new TSP massaged LT1 cylinder heads.

The folks at Texas Speed and Performance hooked us up on the top-end with two of its most popular upgrades for Gen V LT1 engines. The first of said upgrades is its head porting services for Gen V engines (PN 199-LT1GMPORTING). The CNC porting of the stock castings includes a valve job and milling to your specs (we went with a simple resurface to keep compression down). These heads flow 345/226 cfm at .600-inch lift, but continue to climb up to .700-inch (364/230 cfm) – just begging for a high lift camshaft.

“While the port size doesn’t get a lot bigger, we are able to remove some restriction areas and slightly reshape the port for a big improvement in airflow,” Trevor Doelling at Texas Speed told us. “The last thing you want is a huge runner that is lazy. Its crucial to keep the port small and the airflow up. There isn’t any one specific restriction [in the LT1 head] but rather multiple smaller restrictions that add up to a sizable change.”

“Texas Speed has over 22 CNC machines running everyday to produce our LS and LT lineup of cylinder heads,” he concluded. “The LT heads are currently CNC ported on a Centroid B-4250 5-axis machine, and valve jobs are cut on a Newen Contour seat and guide machine.”

TSP makes the process simple; we sent them our cylinder heads and had a complete porting job done, as well as a competition valve job to match the stock valves. TSP also vacuum tested our cylinder heads post-assembly to verify flow.

Combined with our new, stiffer COMP Cams valvesprings (PN 26526TS-KIT) and our previously mentioned COMP camshaft (along with longer 7.825-inch pushrods for the added lift and surfaced cylinder heads), our build is expected to pick up more than 100 horsepower naturally aspirated from these changes.

Concluding the long-block build was TSP’s Gen V DOD delete kit (PN 25-LT1DODDEL-KIT). We chose to incorporate this in the build for a handful of reasons, with the obvious being to run a much higher lift camshaft for more power.

“DOD delete is a no brainer,” Doelling stated. “You get rid of the problematic lifters that fail over time, and you get the ability to run a more aggressive cam lobe compared to what the DOD lifters could handle. The DOD lifters really compromise power potential from a camshaft design perspective, not to mention all of the lifter failures that you see even on stock, unmodified vehicles.”

“We originated the use of plugs for the DOD stacks back in 2014 when the LT engines were released,” he continued. “It works absolutely the same as replacing the valley cover without having to spend the money on a new cover. The goal is to stop the oil flow through the DOD stacks in the block, and the plugs make it cheap and easy to do so. While our DOD delete kit comes standard with the DOD plugs, customers do have the choice of upgrading to a new valley cover in place of the plugs if they prefer. Again, it’s the same end goal with two different approaches. It all comes down to personal preference.”

TSP says that this is the "icing on the cake" when it comes to a heads, cam and intake package for our Pony Wars' Camaro. The kit features 8 DOD plugs that block off the DOD stacks, Gen V head bolts (we upgraded to the previously mentioned ARP components), four new LS-style lifter trays, LS7 lifters, Gen V head gaskets, a new VVT camshaft bolt (and optional balancer bolt), and an optional valley cover gasket.

And, finally, we are clamping our cylinder heads down with a set of ARP 9/16-inch head bolts (PN 234-3710).

That concludes our long-block build for our Pony Wars’ 2017 Camaro SS. With a forged long-block between the fenders of our sixth-generation Camaro, as well as stout ProCharger D-1X, we expect our Camaro to give the Mustang a run for its $15,000!

This competition is backed by some of the biggest names in the automotive aftermarket — including ARPBMR SuspensionCOMP CamsCovercraftDiablosportDyna-BattE3 Spark PlugsFragola Performance PartsHolley Performance ProductsMahle North AmericaMahle MotorsportsMickey Thompson Tires & WheelsProCharger SuperchargersPRWQA1 SuspensionRoyal Purple Synthetic OilSummit RacingTCI AutomotiveWeld Racing, and others — and it is almost at the finish line as we look to return to the track one last time to see who reigns supreme.

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About the author

Harrison Noble

Living in San Diego for most of his life, Harrison was exposed to a variety of cars at an early age. His passion for anything that is fast, or has a V8, brought him to Power Automedia.
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