LS3 Intake Manifold Dyno Shootout!

Written by Richard Holdener on March 3, 2018

Way back in 2015, we performed the mother of all LS intake tests by running 20 different intakes designed for cathedral-port heads . That test included every cathedral-port intake we could get our hands on, including the various factory versions. The problem with doing the mother of all intake tests for the cathedral-port guys is that it left out the LS3 owners. GM eventually replaced the cathedral-port heads with high-flow, rectangular-port heads when they introduced the LS3, L92, and L76 motors (to name a few). Blessed with what were essentially race heads right from the factory (flowing 315 cfm), the rec-port motors offered even more potential than the factory cathedral-port combos. Not surprisingly, the aftermarket jumped on the band wagon to offer all manner of intake combinations for the new cylinder head configuration, so it was only natural that we had to test them. Unlike the previous adventure, we decided to split up the EFI and carbureted intakes and test them separately. Provided here for your viewing pleasure are the results of part 1 on the EFI intakes.

Before getting to the results (like you haven’t already jumped ahead!), we need to point out a few facts, the first of which is that the factory LS3 intake is one of the best OE intakes ever produced. Unlike the previous cathedral-port examples, even the mighty Trailblazer SS (TBSS) manifold, the stock LS3 intake, has proven tough to beat. Oh sure, it is possible to shift power production higher in the rev range with shorter runners, but this usually comes with a trade-off in low-speed torque, sometimes a significant one. This is an important point, as many of these intakes were not designed for our mild cam-only LS3 crate motor (specs on our COMP 54-496-11 hydraulic roller measure 231/247 degrees at .050 and .617/.624-inch lift with a 113 LSA), and would be better suited to something with wilder cam timing, or more displacement, or both. Intakes should be thought of in terms of engine speed (much like a cam). The runner length (and other design variables) determines the effective operating range. Matching this range with the right cam timing, head flow, and displacement, and you have a winning combination.

The internet will be quick to grab the peak numbers from this test and run with them, but there is much more to an intake, or the power curve it produces, than simple peak values. A review of the data will reveal that the difference between the least and most powerful intakes was over 65 hp. This is a significant chunk of change, but peaks only tell part of the story, as acceleration is a function of average power production. Understanding this, we included average power production from 3,100 rpm to 7,000 rpm. We also included torque production at 4,000 rpm, since street driving entails much more time in this part of the power curve than at maximum rpm. The point here is that all of the data is important, and that if you are looking for the very best manifold ever made, you are looking in the wrong place. No such animal exists, so don’t be disappointed. If, on the other hand, you are looking for data to select the best intake for your application, sit back and enjoy.Watch Stock vs. Built vs. Boost vs. Both

Stock LS3 

eBay Price:                         $299

Construction:                      composite

Throttle opening:                 3.698 inches

Throttle body size tested:    FAST 92mm

Fuel rail:                              stock LS3

Injectors:                             FAST 89 lb/hr

Peak power:                        580.5 hp at 6,500 rpm

Peak torque:                       527.9 lb-ft at 5,300 rpm

Ave HP (3,100-7,000):          468.3 hp

Ave TQ (3,100-7,000):          485.8 lb-ft

TQ at 4,000 rpm:                 486.2 lb-ft

What we like:                       OEM quality fit, finish and impressive power

What we don’t:                    Not visually appealing

Our testing began with what is arguably the best factory intake ever offered on an LS. Many aftermarket manufacturers have discovered that the stock LS3 intake is tough to beat. Sure, you can add power higher or lower in the rev range, but there will almost always be some sort of trade-off compared to the stock intake. The GM engineers got this one spot on! Equipped with the factory LS3 intake and FAST 92mm throttle body, the cammed 6.2L crate motor produced peak numbers of 580 hp and 527 lb-ft of torque. Naturally, all testing was run with the same air/fuel and timing values that maximized power production for each manifold. This curve was to serve as the baseline for the remainder of the LS3 intakes.

Stock LY6

eBay price:                         $295

Construction:                      composite

Throttle opening:                 3.715 inched

Throttle body size tested:    FAST 92mm

Fuel rail:                              stock LY6

Injectors:                             Holley 83 lb/hr

Peak power:                        576.5 hp at 6,600 rpm

Peak torque:                       533.4 lb-ft at 5,300 rpm

Ave HP (3,100-7,000):          468.6 hp

Ave TQ (3,100-7,000):          486.0 lb-ft

TQ at 4,000 rpm:                 483.9 lb-ft

What we like:                       factory fitment, good power, and comes on LY6 and L76 truck engines

What we don’t:                    Ugly appearance and not ideal for low-profile applications

The LY6 intake is basically the truck version of the LS3. It seems the truck engineers were every bit as sharp as the Corvette guys, as the LY6 intake produced all but identical power numbers. The truck manifold seemed to favor torque production slightly more than peak power, but only by a few numbers. Equipped with the LY6 intake, the LS3 test motor produced just 576 hp and 533 lb-ft of torque.

Stock LS2 (with adapters)

eBay price:                         $295 (Plus $189 for adapters)

Construction:                      composite

Throttle opening:                 2.960 inches

Throttle body size tested:    FAST 92mm

Fuel rail:                              stock LS2

Injectors:                             FAST 89 lb/hr

Peak power:                        551.9 hp at 6,700 rpm

Peak torque:                       499.1 lb-ft at 5,200 rpm

Ave HP (3,100-7,000):          446.2 hp

Ave TQ (3,100-7,000):          463.9 lb-ft

TQ at 4,000 rpm:                 470.5 lb-ft

What we like:                       Easy to install

What we don’t:                    Low power production using adapters

Running the LS2 intake with rectangle-port adapters is not a good idea. It is tough to beat the factory LS3 intake, but even tougher when adapting the cathedral-port intake to rec-port heads using adapters. Equipped with the adapted LS2 intake, the LS3 test motor produced just 551 hp and 499 lb-ft of torque.

FAST Adjustable LSXR (long runners) 

Summit price:                      $987

Construction:                      composite

Throttle opening:                 3.984 inches

Throttle body size tested:    FAST 102mm

Fuel rail:                              FAST Billet

Injectors:                             FAST 89 lb/hr

Peak power:                        585.8 hp at 6,600 rpm

Peak torque:                       533.9 lb-ft at 5,400 rpm

Ave HP (3,100-7,000):          470.9 hp

Ave TQ (3,100-7,000):          488.2 lb-ft

TQ at 4,000 rpm:                 487.9 lb-ft

What we like:                       Better looking than stock LS3, adjustability

What we don’t:                    Cost and minimal power gains over stock LS3

That the FAST LSXR intake only offered an additional 5 hp over the factory LS3 shows just how little power the GM engineers left on the table. When selecting an intake for a cathedral-port application, the FAST is the go-to choice, but the gains are much less prevalent on the LS3. We did like the adjustability that allowed us to tune the intake to the rest of the combination and intended engine speed. Equipped with the FAST adjustable LSXR intake (long runners), the 6.2L produced 585 hp and 533 lb-ft of torque.

FAST Adjustable LSXR (medium runners) 

Summit price:                      $362 (plus the cost of the intake)

Construction:                      composite

Throttle opening:                 3.984 inches

Throttle body size tested:    FAST 102mm

Fuel rail:                              FAST billet

Injectors:                             FAST 89 lb/hr

Peak power:                        593.4 hp at 6,800 rpm

Peak torque:                       512.8 lb-ft at 5,300 rpm

Ave HP (3,100-7,000):          459.7 hp

Ave TQ (3,100-7,000):          474.4 lb-ft

TQ at 4,000 rpm:                 463.2 lb-ft

What we like:                       Improved peak power

What we don’t:                    Cost and trade-off in torque lower in the rev range on this application

Run with the medium-length runners, the peak power output jumped to 593 hp, but note that torque production dropped through most of the curve. Such is the trade-off inherent in changes in runner length. The shorter runners must be teamed with a cam profile that will allow the motor to rev to the effective operating speed of the runner length. Equipped with the FAST adjustable LSXR intake (medium runners), the 6.2L produced 593 hp and 512 lb-ft of torque.

FAST Adjustable LSXR (short runners) 

Summit Price:                     $362 (plus the cost of the intake)

Construction:                      composite

Throttle opening:                 3.984 inches

Throttle body size tested:    FAST 102mm

Fuel rail:                              FAST billet

Injectors:                             FAST 89 lb/hr

Peak power:                        603.1 hp at 7,000 rpm

Peak torque:                       496.4 lb-ft at 5,300 rpm

Ave HP (3,100-7,000):          449.1hp

Ave TQ (3,100-7,000):          462.7 lb-ft

TQ at 4,000 rpm:                 447.4 lb-ft

What we like:                       Even More Top End Power than medium runners

What we don’t:                    Cost and trade-off in torque on this mild LS3 application

Equipped with the short runners in the Fast LSXR intake, the LS3 really wanted to rev. This combination produced peak power at 7,000 rpm and was the first intake we tested to eclipse the 600hp mark. Though the peak output shined, the short runners once again traded torque production lower in the rev range. This intake combination needed increased displacement and/or wilder cam timing to take advantage of what it had to offer. Equipped with the FAST adjustable LSXR intake (short runners), the 6.2L produced 603 hp and 496 lb-ft of torque.

FAST Adjustable LSXRT (short runners) 

Summit Price:                     $399 (plus the cost of the intake)

Construction:                      composite

Throttle opening:                 3.984 inches

Throttle body size tested:    FAST 102mm

Fuel rail:                              FAST billet

Injectors:                             FAST 89 lb/hr

Peak power:                        603.6 hp at 7,000 rpm

Peak torque:                       495.6 lb-ft at 5,200 rpm

Ave HP (3,100-7,000):          449.0 hp

Ave TQ (3,100-7,000):          462.4 lb-ft

TQ at 4,000 rpm:                 445.0 lb-ft

What we like:                       FAST quality

What we don’t:                    No difference in power compared to standard LSXR top, despite change in plenum volume

For this test, we replaced the standard LSXR upper intake section with the larger LSXRT intake. Often referred to as the truck intake, the LSXRT top simply offers increased plenum volume on this adjustable intake application. This combination was still equipped with the short runners used in the previous test. Equipped with the short runners and FAST LSXRT top, the LS3 produced almost identical power to the standard LSXR top. The plenum volume changed the power output very little on this application. Equipped with the FAST adjustable LSXRT intake (with short runners), the 6.2L still produced 603 hp and 495 lb-ft of torque.

Holley Mid-Rise EFI

Summit price:                      $698

Construction:                      cast aluminum

Throttle opening:                 3.64 inches

Throttle body size tested:    Holley 92mm

Fuel Rail                             Holley

Injectors:                             Holley 83 lb/hr

Peak power:                        564.0 hp at 6,700 rpm

Peak torque:                       500.7 lb-ft at 5,200 rpm

Ave HP (3,100-7,000):          450.0 hp

Ave TQ (3,100-7,000):          466.6 lb-ft

TQ at 4,000 rpm:                 464.4 lb-ft

What we like:                       Versatile, improved hood clearance over Hi Ram

What we don’t:                    Less power than Hi Ram

The Mid Rise offered improved hood clearance compared to the Hi Ram, but the power gains were nowhere near as significant. The Mid Rise accepted a number of different throttle body configurations. It was also possible to run this with a 102mm top, but we jumped to the dual-quad set-up for the next test. Equipped with the single 92mm throttle body, the Holley Mid Rise produced 564 hp and 500 lb-ft of torque.

Holley Mid Rise (dual 4150 TB)

Summit price:                      $399 (plus TBs)

Construction:                      cast aluminum

Throttle body size tested:    dual 4150 (FAST & Accufab)

Fuel rail:                              Holley

Injectors:                             Holley 83 lb/hr

Peak Power:                       577.8 hp at 6,800 rpm

Peak Torque:                      507.8 lb-ft at 5,300 rpm

Ave HP (3,100-7,000):          455.4 hp

Ave TQ (3,100-7,000):          471.3 lb-ft

TQ at 4,000 rpm:                 469.6 lb-ft

What we like:                       Dual-quad coolness and improved hood clearance over Hi Ram

What we don’t:                    Less power than Hi Ram and expense of dual 4150 throttle bodies

It seems the Mid Rise Holley needed more airflow, as replacing the single throttle opening with the dual 4150 throttle bodies definitely improved the power output. The change also shortened the runners slightly. Equipped with the dual 4150 throttle bodies, the Holley Mid rise produced 577.8 hp and 507 lb-ft of torque.

Holley Hi Ram (105mm TB)

Summit Price:                     $780 (plus TB)

Construction:                      cast aluminum

Throttle opening:                 4.140 inches

Throttle body size tested:    Holley 105mm

Fuel rail:                              Holley

Injectors:                             Holley 83 lb/hr

Peak power:                        612.6 hp at 6,900 rpm

Peak torque:                       509.7 lb-ft at 5,000 rpm

Ave HP (3,100-7,000):          462.3 hp

Ave TQ (3,100-7,000):          476.3 lb-ft

TQ at 4,000 rpm:                 458.7 lb-ft

What we like:                       Impressive power, strong visual statement

What we don’t:                    Hood clearance

Things got serious when we installed the 105mm throttle body on the Holley Hi Ram. Holley also offers a 92mm top for the Hi Ram, but you will need the 102mm version on almost any application except a turbo 5.3L. The tunnel-ram intake offered impressive peak performance, but torque production did suffer compared to the stock LS3. Equipped with the Hi Ram and single 105mm throttle body, the LS3 motor produced 612 hp and 509 lb-ft of torque.

Holley Hi Ram (dual 4150)

Retail price:                         $781 (plus TBs)

Construction:                      cast aluminum

Throttle body size tested:    dual 4150 (FAST & Accufab)

Fuel rail:                              Holley

Injectors:                             Holley 83 lb/hr

Peak power:                        619.9 hp at 6,900 rpm

Peak torque:                       515.3 lb-ft at 5,500 rpm

Ave HP (3,100-7,000):          465.1 hp

Ave TQ (3,100-7,000):          477.9 lb-ft

TQ at 4,000 rpm:                 459.9 lb-ft

What we like:                       Dual-quad tunnel rams look amazing

What we don’t:                    Hood clearance is not ideal and having to purchase two 4150s

Like the single throttle body version, the dual-quad Hi Ram excelled at high-rpm power production. In fact, it took top honors in this test by producing 620 hp (okay, 619.9 hp) at 6,900 rpm. Obviously the combination required more airflow than the single throttle body could muster, so the dual 4150 throttle bodies allowed the system to breathe. There was also a slight change in the plenum volume between the two tops for the Hi Ram. Equipped with the dual 4150 throttle bodies, the Hi Ram produced 619 hp and 515 lb-ft of torque.

Holley Sniper (low)

Summit price:                      $545

Construction:                      fabricated aluminum

Throttle opening:                 4.090 inches

Throttle body size tested:    Holley 105mm

Fuel rail:                              Holley

Injectors:                             Holley 83 lb/hr

Peak power:                        608.7 hp at 7,000 rpm

Peak torque:                       501.1 lb-ft at 5,500 rpm

Ave HP (3,100-7,000):          453.6 hp

Ave TQ (3,100-7,000):          466.9 lb-ft

TQ at 4,000 rpm:                 449.0 lb-ft

What we like:                       Ominous black finish, easy to install, low profile

What we don’t:                    Short runners limit torque production

These Sniper intakes have become popular, so we were excited about testing the different versions. Essentially, they differed by way of runner length, and this version offered the shortest runners. This meant it offered the lowest profile, but the short runners (as always) traded peak power for torque production. While the Sniper offered more peak power than the factory LS3, torque production suffered through much of the rpm range. Equipped with the low-profile Sniper, the 6.2L produced 608 hp and 501 lb-ft of torque.

Holley Sniper (high)

Retail Price:                        $545

Construction:                      fabricated aluminum

Throttle opening:                 4.090 inches

Throttle body size tested:    Holley 105mm

Fuel rail:                              Holley

Injectors:                             Holley 83 lb/hr

Peak power:                        605.9 hp at 6,900 rpm

Peak torque:                       503.5 lb-ft at 5,300 rpm

Ave HP (3,100-7,000):          456.4 hp

Ave TQ (3,100-7,000):          470.5 lb-ft

TQ at 4,000 rpm:                 454.0 lb-ft

What we like:                       Polished appearance, easy to install, still low profile

What we don’t:                    Short(er) runners limit torque production

These Sniper intakes sure looked the part (especially the polished ones), and many will be purchased on looks alone. This version featured slightly longer runners than the low version. Either version should easily fit under the hood where a factory manifold works. Despite a slight increase in runner length, this version also traded peak power for torque production compared to the stock manifold. Equipped with the Sniper, the 6.2L produced 605 hp and 503 lb-ft of torque.

Edelbrock Vic Jr.

Summit price:                      $425

Construction:                      cast aluminum

Throttle opening:                 4150

Throttle body size tested:    4150

Fuel rail:                              Edelbrock

Injectors:                             Holley 83 lb/hr

Peak power:                        600.4 hp at 6,900 rpm

Peak torque:                       503.5 lb-ft at 5,400 rpm

Ave HP (3,100-7,000):          452.8 hp

Ave TQ (3,100-7,000):          465.8 lb-ft

TQ at 4,000 rpm:                 451.2 lb-ft

What we like:                       High quality, Looks/performs great, can run carb air cleaners

What we don’t:                    Short runners designed for higher engine speeds

The Edelbrock Victor Jr. is the smallest of the three Victors we tested, but it still managed to exceed the 600hp mark. The quality was good and looking back we would like to have tried an adapter and larger (4500) throttle body to see if it was restricting the airflow of this (and the 4150 Super Victor) combination. Equipped with the Edelbrock Victor Jr., the LS3 produced 600 hp and 503 lb-ft of torque.

Edelbrock Super Victor 4150

Summit price:                      $461

Construction:                      cast aluminum

Throttle opening:                 4150

Throttle body size tested:    4150

Fuel rail:                              Edelbrock

Injectors:                             Holley 83 lb/hr

Peak power:                        601.6 hp at 6,900 rpm

Peak torque:                       500.3 lb-ft at 5,500 rpm

Ave HP (3,100-7,000):          450.9 hp

Ave TQ (3,100-7,000):          463.9 lb-ft

TQ at 4,000 rpm:                 449.5 lb-ft

What we like:                       High quality, looks/performs great, power to grow with other upgrades

What we don’t:                    Single-plane designed for higher engine speeds

The Edelbrock Super Victor 4150 produced almost the same power curve as the smaller Victor Jr., but like most of these short-runner intakes, they really needed more motor. Even more than the Victor Jr., we suspected the Super Victor would benefit from a larger throttle body and we found this to be true once we tested the 4500 version of the manifold. These intakes will continue to be popular for high-rpm race applications. Equipped with the 4150 Super Victor, the LS3 produced 601 hp and 500 lb-ft of torque.

Edelbrock Super Victor 4500

Summit price:                      $541

Construction:                      cast aluminum

Throttle opening:                 4500

Throttle body size tested:    Accufab 4500

Fuel rail:                              Edelbrock

Injectors:                             Holley 83 lb/hr

Peak power:                        613.8 hp at 6,900 rpm

Peak torque:                       504.2 lb-ft at 5,700 rpm

Ave HP (3,100-7,000):          455.2 hp

Ave TQ (3,100-7,000):          467.8 lb-ft

TQ at 4,000 rpm:                 450.1 lb-ft

What we like:                       High quality, Looks even more impressive with the 4500 flange

What we don’t:                    Runner length still designed for even higher engine speeds

We suspected the Victor series intakes were limited by the 4150 throttle body used for testing, even on this mild LS3. These intakes really needed wilder cam timing, or more displacement, or (ideally), both, to really strut their stuff. None of them belonged on a cam-only LS3, and should be used on a motor that runs to at least 8,000 rpm (not just 7,000 rpm). The 4500 version of the Super Victor produced more power than the 4150 versions. Equipped with the 4500-series Super Victor, the LS3 produced 613 hp and 504 lb-ft of torque.

Edelbrock Cross Ram

Summit price:                      $1,283

Construction:                      cast aluminum

Throttle opening:                 3.64 inches

Throttle body size tested:    Holley & FAST 92mm

Fuel rail:                              Edelbrock

Injectors:                             FAST 89 lb/hr

Peak power:                        590.2 hp at 6,600 rpm

Peak torque:                       543.3 lb-ft at 4,800 rpm

Ave HP (3,100-7,000):          474.8 hp

Ave TQ (3,100-7,000):          493.5 lb-ft

TQ at 4,000 rpm:                 498.2 lb-ft

What we like:                       Impressive appearance, cross-ram coolness, unique

What we don’t:                    Expense, Set up for drive-by-wire throttle bodies. We’d like manual options

There is just something about a dual throttle-body cross-ram that screams performance. Pop the hood on an intake like this and people are going to stare. The Edelbrock Cross Ram may not have offered the highest peak power of the test, but it did offer the highest peak torque (543 lb-ft) and the highest average power and torque numbers. Equipped with the Edelbrock Cross Ram, the LS3 produced 590 hp and 543 lb-ft of torque.

Mast 4150 Single-Plane

Mast price:                          $1,749

Construction:                      cast aluminum

Throttle opening:                 4150

Throttle body size tested:    4150

Fuel rail:                              Mast

Injectors:                             Holley 83 lb/hr

Peak power:                        609.1 hp at 6,900 rpm

Peak torque:                       506.5 lb-ft at 5,300 rpm

Ave HP (3,100-7,000):          454.2 hp

Ave TQ (3,100-7,000):          467.1 lb-ft

TQ at 4,000 rpm:                 450.5 lb-ft

What we like:                       Amazing CNC work, the kind we hate to ruin by running

What we don’t:                    Expensive and we feel it needs a 4500 flange (which they offer)

The single-plane intake from Mast Motorsports performed flawlessly as we have come to expect from their products. Like the other single-plane intakes, it produced peak power high in the rev range and needed much more motor than our wimpy little LS3. The two-piece design allowed full CNC porting. Too bad we didn’t have a motor to allow these intakes to shine.  Equipped with the Mast 4150 intake, the LS3 produced 609 hp and 506 lb-ft of torque.

Speedmaster IR Downdraft

Jegs price:                          $2,060

Construction:                      cast aluminum

Design:                               individual runner

Throttle openings:               2.0 inches (x8)

Fuel rail:                              Speedmaster

Injectors:                             FAST 89 lb/hr

Peak power:                        601.8 hp at 6,900 rpm

Peak torque:                       508.8 lb-ft at 5,400 rpm

Ave HP (3,100-7,000):          460.5 hp

Ave TQ (3,100-7,000):          475.0 lb-ft

TQ at 4,000 rpm:                 456.9 lb-ft

What we like:                       Individual runner intakes just look and sound amazing. The polished finish would be right at home on a show car.

What we don’t:                    We’d like to see them use a GM TPS for easy hook-up and air cleaners are always an issue with IR system (though most don’t run them).

Obviously the Speedmaster downdraft had no issues with airflow. Having no less than eight individual throttle bodies ready and able to feed the flow needs of each cylinder, the IR system offered plenty of airflow. The system was polished to perfection and the center-pivot throttle assembly worked well. As with any IR system, the key to success is not tuning at WOT, but rather getting the eight individual systems to cooperate at idle and part throttle. Even more than some of the other polished intakes, LS enthusiasts will likely want this based on looks alone. Equipped with the Speedmaster IR Downdraft system, the LS3 produced 601 hp and 508 lb-ft of torque.


LATE TO THE PARTY

The one thing we can count on when testing “all” the LS3 intake manifolds is missing one or two. After running 20 different LS3 intake configurations, we came across a couple of stragglers who were late to the party. Naturally we wanted to include both the Edelbrock Pro-Flo XT and the Performance Designs Carbon pTR, but this was easier said than done. Unfortunately, between the first round of testing and when the new arrivals showed up at the dyno, we had a problem with our LS3 crate motor. During testing for another story, we got a little greedy with the rpm and managed to tag a few intake valves. We were not able to get the problem solved in time to run the two new intakes, so we did the next best thing, we ran them on another test engine. Rather than not include them in the test, we compared them to the stock LS3 intake on a larger 415 stroker (Wiseco forged internals, AFR LS3 heads and healthy Comp Cam) we had sitting around. While you won’t be able to compare them to the others, you can still see how they fared against the stock LS3 intake.

Stock LS3 (415 stroker)

eBay price:                         $299

Construction:                      composite

Throttle opening:                 3.698 inches

Throttle body size tested:    FAST 92mm

Fuel rail:                              stock LS3

Injectors:                             FAST 89 lb/hr

Peak power:                        626.8 hp at 6,300 rpm

Peak torque:                       568.4 lb-ft at 5,300 rpm

Ave HP (3,100-7,000):          506.8 hp

Ave TQ (3,100-7,000):          523.8 lb-ft

TQ at 4,000 rpm:                 527.8 lb-ft

What we like:                       OEM quality fit, finish and impressive average power

What We don’t:                   Not great looking

To establish a new baseline with the larger 415 stroker, we started once again by running the big-inch LS3 with the factory LS3 intake. Once again, the factory offering demonstrated its versatility by producing impressive power on a motor it was never designed for. Equipped with the factory LS3 intake and FAST 92mm throttle body, the AFR-headed, 415 Wiseco stroker produced 627 hp at 6,300 rpm and 568 lb-ft of torque at 5,300 rpm. You will notice that these peak engine speeds nearly match the cam-only 6.2L run with the stock manifold. As with all of the testing, we maximized the power output of each combination with optimum air/fuel and timing values. These power curves were to serve as the baseline for the other two intakes tested on the 415 stroker.

Edelbrock Pro-Flo XT LS3 (415 stroker)

Summit price:                      $659

Construction:                      cast aluminum

Throttle opening:                 3.628 inches

Throttle body size tested:    FAST 92mm

Fuel rail:                              Edelbrock

Injectors:                             FAST 89 lb/hr

Peak power:                        655.6 hp at 7,000 rpm

Peak torque:                       550.6 lb-ft at 5,800 rpm

Ave HP (3,100-7,000):          498.4 hp

Ave TQ (3,100-7,000):          512.5 lb-ft

TQ at 4,000 rpm:                 487.4 lb-ft

What we like:                       Sleek tunnel ram, black finish, easy installation

What we don’t:                    Short runners tend to limit mid-range torque production

We had very good success with the Pro-Flow in our test on the cathedral-port intakes, and this rec-port (LS3) version continued the trend. The Edelbrock Pro-Flo XT showed its high-rpm strength by making peak power at 7,000 rpm, even on the big-inch LS3 stroker. Racers have run these intakes with great success on high-rpm, turbo applications. Equipped with the Pro-Flo XT, the 415 stroker produced 656 hp and 551 lb-ft of torque, which represented a gain of nearly 30 hp over the stock intake. The peak torque output was down 17 lb-ft, but torque suffered through much of the rev range, something we have come to expect with short-runner intakes (at least compared to the stock intake).

Performance Design Carbon pTR (415 stroker)

Estimated retail:                  $1,250 (FAST will offer and all-polymer version near $1,000)

Construction:                      polymer & carbon fiber

Throttle opening:                 4.103 inches

Throttle body size tested:    FAST 102mm

Fuel rail:                              Performance Design

Injectors:                             FAST 89 lb/hr

Peak power:                        653.0 hp at 6,600 rpm

Peak torque:                       570.8 lb-ft at 5,100 rpm

Ave HP (3,100-7,000):          508.6 hp

Ave TQ (3,100-7,000):          524.2 lb-ft

TQ at 4,000 rpm:                 516.2 lb-ft

What we like:                       Impressive carbon fiber exterior finish

What we don’t:                    Expense (This may be reduced with the FASYT polymer version) & fitment

The Carbon pTR was one of the intakes we were excited to test. Like the Edelbrock X Ram and Speed Master downdraft system, the Carbon pTR represented something different. We see lots of the other, more common intake varieties in testing, but guys at the dyno always stop and take a hard look at anything sporting a carbon fiber exterior. You won’t likely find another version at your local drag race or hot spot, at least not until the all-polymer version from FAST hits the scene. The intake features adjustable runner lengths, but this stroker combination ran best with the longest runners. Equipped as such, the Carbon pTR produced 653 hp and 571 lb-ft of torque. Despite the shorter runners, the Carbon pTR produced more peak torque than the stock LS3 intake.


Sources:

Accufab
909.930.1752
www.accufabracing.com

ARP
800.826.3045
Arp-bolts.com

Comp Cams
901.795.2400
www.compcams.com

Edelbrock
310.781.2222
www.edelbrock.com

FAST
877.334.8355
www.fuelairspark.com

Gandrud Chevrolet
800.242.2844
parts@gandrud.com

Holley/Hooker/Weiand
270.782.2900
www.holley.com

Lucas Oil
Lucasoil.com

Mast Motorsports
936.560.2218
mastmotorsports.com

Performance Design
855.909.0990
Performancedesign.com

Summit Racing
888.939.7497
summitracing.com

Speedmaster
909.605.1123
Speedmaster79.com

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