January 1, 2001

Just out of curiosity, I took down several of my big boxes of back issues of MMFF, and thumbed through just about every Mustang magazine for the past six to seven years in search of intake manifold comparisons. I'm talking about one heck of a lot of magazines to go through, as my search even included tests run by the competition (other Mustang magazines). After my exhaustive search, I came across a familiar trend. The vast majority of the intake manifold testing for any 5.0-based motor configuration (strokers included) has been run with one of several major handicaps, but as we shall see, the handicaps were there by design. Though it is likely that every conceivable intake available for the 5.0 has been subjected to the rigors of the dyno, in all the tests (even those run by yours truly) there was almost always something left on the table.

01. Instructions for an MM&FF intake shoot-out: Build one tenacious test motor. Install said motor on dyno, add intake and flog till finished. Repeat as necessary. In our case, we followed the instructions to the tee--four times.

In the beginning, there were ported stock H.O. intakes, followed shortly by the vastly improved GT-40. The GT-40 was and continues to be the aftermarket intake that all others are measured by. This particular test is no different, as we elected to run our test motor with a GT-40 before running the remainder of the intakes. After the Ford Racing GT-40, the aftermarket began building any number of upper intakes (some may actually predate the GT-40) and then manufacturers jumped in whole hog and gave us the overwhelming conglomeration of intakes now available for the 5.0 (and 5.8 variants). In looking at the available intakes, the vast majority are of the long-runner variety. Sure, box uppers such as the Comp Cams polymer, Downs and Hurricane uppers are available for a variety of different lower 5.0L manifolds, but the Performer (& RPM), Cobra and Trick Flow Specialties Street manifolds tend to be the most popular due to their long-runner design, which offers an abundance of usable power in the rpm most often seen on the street. With gobs of torque and a power curve that peaks between 5500 rpm and 6000 rpm, the long-runner intakes are tough to beat for street and most strip applications.

02. The intake test motor was a 10.5:1 CHP 347 Street Fighter. We figured the addeddisplacement would help tax the airflow of the three intake manifolds.

Let's face it, the long runner intakes make the most sense for the vast majority of 5.0 applications for another related reason. The vast majority of motors out there prowling the streets are of the hydraulic-roller persuasion. A marvel of technology that combines excellent friction reduction with set-it-and-forget-it adjustment schedules, the hydraulic roller cam has a lot going for it. The hydraulic roller valve train is also one of the limiting factors to power and the reason to choose an intake that signs off at 6000 rpm. Given the relatively hefty weight of the hydraulic roller lifter, the system is not designed to run much above 6000 rpm without experiencing lifter bounce (not quite the same as rpm-induced valve float). Look for a detailed examination of this phenomenon in a later test and possibly even a cure that will allow extended revs (not added spring pressure) from the good folks at Comp Cams in a future issue. For now, simply accept the fact that a hydraulic roller lifter is limited to somewhere near 6000 rpm, plus or minus a few hundred rpm.

03. The CHP Street Fighter kit came with a steel crank (3.4-inch stroke), steel h-beam rods and forged pistons with valve reliefs to accept a number of different head/valve configurations.

In most street and strip 5.0 applications, a 6000 rpm ceiling on power is both more than sufficient and a blessing in disguise. Given the fact that supercharged motors have produced in excess of 700 hp at 6000 rpm, there is obviously plenty of power to be had from a 5.0 or stroker version even with the near-6000 rpm rev limit. Keeping the revs near 6000 rpm also makes life much easier on parts, as engine life decreases dramatically with increased engine speed. Keeping the parts alive should be paramount to any 5.0 enthusiast. The valvetrain induced 6000-rpm rev limit (please, no letters about the 6250 factory rev limiter or how your motor revs to 7000 rpm with hydraulic roller lifters) works perfectly with a long-runner intake to produce an exceptional torque and horsepower curve, usually peaking just short of 6000 rpm. Given the perfect match of valvetrain dynamics and long-runner intakes, what more could you ask for?

04. The short-block was topped off with a set of Air Flow Research 185 cylinder heads. Note that we were checking piston to valve clearance for our big solid roller cam.

What more, indeed? Don't racers and enthusiasts alike always ask for more?Not long after the long-runner intakes became available, short(er) versions were soon offered. Edelbrock gave us the long-runner Performer and Performer RPM versions, but soon stepped up with the Victor 5.0 version that offered much more rpm capability than our 6000 rpm motors could effectively use. The same scenario was true at Holley with the SysteMax II not to mention TFS and its R-series intake. Previous intake comparison tests revealed that, like the box uppers bolted to a ported lower, these race manifolds were just getting started when shut down at 6000 (or 6250) rpm. More often than not, a comparison between these intakes and a GT-40, Cobra or Performer RPM resulted in the race intakes taking a back seat to the "smaller" street-oriented manifolds.

05. Comp Cams supplied the Xtreme Energy 292R Street Roller cam and valve train for our test motor. The healthy cam sported 254/260 degrees of duration, something that allowed our test motor to rev and demonstrate the effectiveness of the trio of "Super" intakes.

The reason was not so much that the race intakes lacked air flow or power potential but that the test parameters were all stacked in favor of the long(er) runner, street intakes. Running a TFS R, Holley SysteMax II or Victor 5.0 intake on a stock or even a mild 5.0, especially one with a hydraulic roller valve train is an exercise in intake misapplication. The result would be that the motor runs out of revs before it runs out of intake. Installing the same intake on the correct motor combination is a whole 'nother matter. Or is it?

What these performance-oriented intakes needed in order to strut their stuff was a test motor that had the power output to tax their flow capability and the rpm potential to find a peak power number. Basically, these intakes needed a real motor!

To properly run this intake test, we built just such a motor. Since the best way to produce horsepower is with displacement, we opted to start not with a 302 but rather with a 347 short-block. The 347 was assembled by Coast High Performance and featured a steel crank, h-beam rods and forged pistons. The displacement combined with the piston design and milled Air Flow Research 185 heads produced a 11.5:1 static compression ratio.

06. The test motor was equipped with 36 lbs.- hr. injectors and a like calibrated 77mm mass air meter.

Having run the AFR heads on a 392 that produced 535 hp, we were confident that they would provide plenty of power potential for our intake test. Since several of the six different intakes would likely take the engine well beyond 6000 rpm, we needed a cam that offered a powerband that didn't peak below that figure. Knowing that revs were in our future, we ditched the hydraulic roller valve train and went straight for one of the solid roller profiles in the Comp Cams catalog. Wanting plenty of cam to tax the intakes, we selected the biggest, baddest, solid Xtreme Energy Street Roller profile offered by Comp Cams. The XE292R offered a 254/260 duration profile (at .050), a .621/.627 and a 110 lobe separation angle. Though a Street Roller, this was one healthy cam (too healthy for our piston-to-valve clearance, as we would later find out).

07. This Extender from Ford Racing allowed us to rev right by the factory 6250 rpm rev limiter in the stock EEC-IV computer. It also allowed us to set a desired air/fuel ratio at the elevated engine speeds.

The cam, heads and even displacement were all chosen in an effort to basically optimize the motor for the three "Super Intakes" used in the first part of our two-part intake test. Designed to make peak power higher than their longer-runner relatives (Victor vs. Performer, TFS R vs Street and SysteMax II vs. I), these intakes required just such a motor to demonstrate their true worth. The AFR 185 heads offered plenty of airflow, while the cam offered plenty of rpm potential.

The final ingredient in our test motor was added displacement versus a typical 302. How does the displacement effect rpm potential and intake tuning you ask? Without a detailed explanation that might well run into several more pages, an intake used on a 302 will make peak power higher than an identical 347. For instance, a GT-40 used on a 302 will make peak power higher than on a 347. The added displacement tames the cam profile and requires more airflow as it produces more power. The flow rate of the long-runner intake becomes taxed sooner in the rpm band on a 347 than an identical 302.

08. A trio of Accufab throttle bodies were used during this intake test. The 70mm unit was run on the GT-40 intake, while the 75mm throttle body was utilized on the three other intakes. The beefy 90mm unit was employed in the second part of the intake test (see part two next month).

Not surprisingly, a 347 that produces more power than a 302 requires more intake flow to do so. Running the same intake lowers the rpm where the motor makes peak power. The difference can be as little as 100 rpm and as much as several hundred rpm, but there will be a difference. With the basics of the 347 test motor set for our journey beyond 6000 rpm, we finished it up with a number of other performance components. The ignition chores were handled by an MSD Billet (EFI) distributor and matching MSD coil. Once we had all the wiring hooked up properly to the EEC-IV, the motor ran the numerous intake manifold tests without a hitch. That is to say the MSD ignition components ran perfectly. In addition to the ignition, we fitted the 347 with a set of 13/4-inch long-tube Hooker headers. The exhaust was run open behind the headers save for a set of 14-inch collector extensions. We did not want to limit the power of the motor (or intakes) by limiting exhaust flow. The open headers and extensions allowed optimized exhaust flow for our intake manifolds. The motor was run on the SuperFlow engine dyno without any of the normal accessories (water pump, AC, PS, etc.). We elected to use a CSI electric water pump on the test motor to keep the water temperature stabilized during the hard dyno runs.

09. Our first order of business was to establish a baseline with the GT-40 intake. Our 347 pumped out 450 hp and 447 lbs.-ft. of torque using the tubular intake.

We have run literally hundreds of dyno pulls with the CSI electric water pump on numerous different 5.0-based motors and it has not complained once. Additional finishing touches to the 347 test motor included a high-volume oil pump, Coast High Performance deep-sump oil pan and matching pick up. The final element was a set of Comp Cams 1.6 ratio aluminum roller rockers.

10. The inlet on the GT-40 typically measures 65mm. Ours had been previously beenmodified to accept a slightly larger unit.

Before running the 347 test motor with a GT-40 intake to establish a baseline, we needed to solve one important problem. The intake manifolds were scheduled to run with a stock EEC-IV computer, 36 lbs.-hr. fuel injectors and matching Pro M (calibrated) mass air meter, but we needed to figure out a way to exceed the 6250 rpm rev limit imposed by the factory computer. Our first thought was to call on the experts at PowerTrain Dynamics to burn us custom chips for each intake with the rev limiter removed. Since we were running a real-time air/fuel mixture meter on the dyno, each intake combination could be optimize by PowerTrain. Though this might have been a great way to go, we eventually decided against it for one very good reason. Most readers out there do not have access to a handful of custom (dyno verified) computer chips to fully optimize their 347 combination. Rather than take advantage of our ability to do just that, we decided to make the test more real world (what the average enthusiasts might actually have) and simply use the computer, calibrated meter and a Ford Racing Extender to probe the upper limits of the rev range on our test motor.

11. The inlet of the GT-40 would not accept the larger 75mm throttle body so we elected to install a 70mm unit.

Not only did the Extender from Ford Racing solve our rpm problem, but it was also easy to use (a big benefit to enthusiasts). With only two different adjustment knobs, it was hard to get confused about the "programming" of our test motor. Basically, the pair of knobs on the Extender were to adjust the new rev limit and desired air/fuel mixture. Since the Extender adjusted the fuel tables based on a desired air/fuel ratio, we were required to hook up the two factory oxygen sensors to the dyno harness.

For our testing purposes, the rev limit dial on the Extender was set for 7100 rpm, while the desired air/fuel ratio was set conservative at 12.8:1. Though peak power will be much better at 13.2:1, we elected to adjust a conservative number to see how effective (and accurate) the Extender was at adjusting our air/fuel mixture.

12. After removal of each intake, the matingsurfaces were cleaned and prepped. We used Fel Pro 1262 intake gaskets and a bead of silicone at each end to seal each lower intake. Note the shirt worn by the assistant. How many Ford guys do you know that have climbed Kilimanjaro ?

We also had an Accufab adjustable fuel pressure regulator on the factory fuel rail to make further air/fuel adjustments. Though we relied on the timing table of the factory EEC-IV, we did maximize power by adjusting the static timing up to 16 degrees. Since we were using 100 octane unleaded fuel in our 11.5:1 347, we figured that 16* of static timing was plenty safe.

Once the motor was assembled and hoisted onto the dyno, we installed the GT-40 intake to begin the test. Unlike the three other three intakes run in the first part of this intake shoot-out, the GT-40 intake was not box stock. A modified GT-40 was run for two reasons. The first reason was that we figured that no enthusiast would run a bone-stock GT-40 on such a great motor. The second reason was that we had a couple of other GT-40-based upper intakes to test for the second part of our intake shoot-out and wanted to make sure they flowed as best they could. To that end, we elected to run a stock GT-40 upper intake on an Extrude Hone ported GT-40 lower intake to establish a baseline. The ported lower would come in handy later when we tested the Comp Cams box and modified Cobra upper intakes. Though the other three intakes (TFS R, Holley SysteMax II and Victor 5.0) were all run with the recommended 75mm throttle body, the throttle opening in the stock GT-40 upper was too small to run the 75mm throttle body. The GT-40 was tested with a 70mm throttle body.

13. The next intake to be tested was the TFS R intake from Trick Flow Specialties. This intake upped peak power to 475 hp but torque fell to 422 lbs.-ft. compared to theGT-40. We would see this as a trend with all of the intakes.

After a few pulls to establish the air/fuel mixture and check out how well the Extender worked, the GT-40-equipped 347 was run right past the 6250-rpm factory rev limit all the way to 6600 rpm. With the GT-40, the 347 posted some impressive power numbers. The peak torque checked in at 447 lbs.-ft. at 4700 rpm, while the peak power reading of 450 hp was all the way up at 6600 rpm. Unlike other intakes, we could not load the 347 any lower than 3300 rpm. This was due to the torquey nature of the long-runner GT-40 intake. With our baseline in hand, we began our rev-happy intake adventure.

The next intake installed on the 347 test motor was the TFS R intake. As the top dog in the series of three offerings from TFS, the R series intake featured shorter and larger runners compared to its long-runner siblings.

14. Though specified to accept a 75mm throttle body, the inlet on this particular TFS R upper intake actually measured much closer to 70mm.

The short runners with large cross-sections made it a perfect choice for our healthy 347 test motor. The runner specifications on this TFS R intake were quite similar to the other two desperadoes in this shoot out. Though we were most interested in the power curve generated by the three different upper and lower intake combinations, we also took into account the ease of installation and general finish of the contestants. The TFS R intake got high marks for cool factor as well as ease of installation.

Unlike the Holley, the six bolts securing the TFS R upper intake to the lower intake were accessible from the top of the manifold (similar in concept to the GT-40). This compares nicely to the Saleen /Vortech intake that requires a bit of dexterity and a custom tool to reach the mounting bolt positioned under the middle section of the plenum. One interesting note about the TFS R intake was that though the TFS literature called out for a 75mm throttle body, the opening in our intake was much closer to 70 mm than 75mm. It is possible that our intake (from Westech) was an early pre-production system that had not received the latest machining, but at any case, the throttle opening was somewhat smaller than expected. As it turned out, none of the intakes actually came with 75mm openings.

15. Like the TFS R, the inlet on the Holley did not measure a full 75mm. The Holley was slightly larger than the TFS R at 72.5mm, but still a few shy of the specified 75mm.

After removing the GT-40 and cleaning our sealing surfaces, a fresh coat of silicone was applied to the front and rear valley rails and the TFS R lower intake was set into place. We had previously swapped over the various sensors and injector hardware from the GT-40 lower. Once the lower was torqued into place, the upper was given the same treatment. Then came the 75mm (Accufab) billet throttle body and we began to connect the engine harness, dyno wiring and fuel system. The Pro-M meter was the last to get plugged in and as distributor removal was not necessary to facilitate the intake swaps, the timing was left in the same position for the remainder of the testing. We were anxious to see the first of the big three intakes run on our test motor, as we had high hopes for the rpm potential of the TFS R.

16. Similar in external appearance to the TFS R, the Holley SysteMax II demonstrated theeffectiveness of its longer runners byproducing significantly more torque thaneither of the other two intakes. The Holley alsoposted impressive peak power numbers at474 hp and 436 lbs.-ft.

After the oil and water were brought up to temperature, we saw just how much extra power was available from these larger manifolds. After some playing with the adjustable fuel pressure regulator to bring the air fuel mixture in line, the TFS R intake posted peak numbers of 475 hp at 6400 rpm and 422 lbs.-ft. of torque at 5100 rpm. The intake swap had netted a 25 hp gain over the GT-40 baseline, but the added top-end power came with a price. The TFS R intake was down on torque compared to the GT-40 to the tune of 25 lbs.-ft.

17. The inlet of the Victor 5.0 was the only one of the three to actually spec out at 75mm.

In a nutshell, the larger intake traded top-end horsepower for low and mid-range torque.

Even before the motor had a chance to cool, we ripped off the TFS R intake to make room for the Holley SysteMax II intake. If you can look past the brilliant flash plating (shiny exterior) the Holley and TFS R intake look similar on the outside. Both upper intakes feature a large V-shaped upper intake aft of the throttle opening that extend back to the plenum. The plenum then arcs into the runners that connect the upper intake to the lower intake.

18. Unlike the other two upper intake, the design of the Victor allowed access to the runner for porting. Of course this is irrelevant if the intakes are to be Extrude Hone ported.

Internally, the TFS and Holley intakes differ substantially. The Holley features not only longer (by about an inch) but also odd-shaped intake runners. Unlike the TFS R and Edelbrock Victor 5.0, which utilized traditional rectangular ports (the mating surfaces that join the upper and lower intakes), the Holley featured odd-shaped runners that resembled distorted rectangular semi-circles. Though the shape of the runners were somewhat unconventional, the results were what counted and odd shaped or not, the Holley posted some pretty impressive numbers especially in the torque category. The Holley was the most difficult of the three to install, with a time-consuming center bolt (under the throttle body) making life difficult, though by no means impossible. The plating made the Holley the brightest of the bunch, which might make it a favorite to those inclined to show off what's under the hood.

Installation difficulties aside (what's a few extra minutes?), the Holley showed that the time was well spent as it easily out-torqued the TFS R intake and missed the peak output of the TFS R by a mere 1 hp (474 hp vs. 475 hp).

19. The Edelbrock intake was not without its faults, as it refused to go on ourtest motor. Installation required grinding edges of the lower intake.

Though 1 horsepower is really splitting hairs, the extra 14 lbs.-ft. of peak torque is anything but. The longer runners in the Holley SysteMax II intake no doubt contributed to the added torque, but the extra grunt did not cost any peak horsepower. Generally there is a tradeoff with horsepower and torque. The Holley intake design bolstered torque production over the TFS R without any sacrifice in peak power.

As with the TFS R, the Holley lost out to the torque-champ GT-40 down low, but bettered the tubular intake as the revs increased. The added torque production of the Holley intake (over the TFS R) is evident in the fact that the Holley bettered the GT-40 baseline at 5250 rpm, some 250 rpm sooner than the TFS R. Note the two humps (not quite a dual torque peak) in the torque curve of the 347 equipped with the Holley intake. This is a function of the efficiency of the long runners in the intake and the motor coming up on the cam.

20. These small protrusions on the AFR 185 heads stopped the Edelbrock from sliding into place. Once treated to some simple grinding, the Edelbrock went right on.

The Holley SysteMax bested the GT-40 by 5250 rpm, much earlier than the TFS R intake. Though the Holley offered a better torque curve, the additional torque production did not cost any top-end power. The Holley was only down by 1 hp compared to the TFS R intake. Like the TFS R, the Holley was down substantially to the GT-40 in the low and mid-range.

The final intake to be tested in part one of our "Super" intake shoot-out was the Edelbrock Victor 5.0. Designed as a step up the performance ladder from the Performer and Performer RPM, the Victor was designed for high rpm power production. Unlike the other two 5.0 intakes in the Edelbrock stable, which share a common lower manifold, the Victor is a clean sheet of paper design that incorporates a dedicated lower manifold with raised runners that mate to the short runner upper intake to produce a high-rpm EFI intake worthy of the Victor name.

21. Like the Edelbrock shown here, all of the intakes received the various sensors, fuel rails and injectors prior to testing.

In looking through the Edelbrock catalog, the pages are full of the trio of intakes, heads and cam components. Edelbrock has done extensive research (both computerized and on the dyno) to come up with components that work best as dedicated packages. For a significant improvement over a stock intake, look no further than the Performer. The next step up the performance ladder is the Performer RPM. As the name implies, the Performer RPM is designed to produce better breathing (usually from larger and shorter runners) than the standard Performer to promote better power production at slightly high engine speeds. For a maximum effort, the Victor is the next logical step.

During our testing, the Victor 5.0 lived up to its performance namesake by besting the other two intakes with the highest peak horsepower reading. Where the TFS R and SysteMax II intakes signed off near 475 hp, the Victor 5.0 kept on pulling to reach 481 hp at 6600 rpm. The Victor 5.0 out-torqued the TFS R intake by posting a peak torque reading of 426 lbs.-ft. at just 4900 rpm (lower than the other two). Like the TFS R, the Victor 5.0 fell prey to the torque of the Holley manifold and lagged behind the Holley until 6150 rpm. From 6150 rpm to 6700 rpm, the Edelbrock demonstrated what short, high-flowing runners can do by besting the other two manifolds. Oddly enough, the Edelbrock was the only intake of the three to give us installation problems. The lower intake refused to go on past the small ridges in the AFR 185 heads (see photo).

The problem did not occur with the Holley or TFS lower intakes. Some minor grinding on the edges of the Edelbrock got us back under way, where the upper intake was the easiest of the three to install.

As with the two other "Super" intakes, the Victor 5.0 lost big torque down low to the GT-40, but picked up big time once the revs reached 5500 rpm. With our three intakes out of the way, you'd think we would be satisfied. Wrong. After running these three (four including the GT-40), we grabbed another trio and subjected the 347 test motor to even more abuse. Check out the results in part two of our "Super" intake shoot out.

GT-40 vs. TFS R
A number of things are obvious from this graph. The first thing is that the TFS R made a great deal more power than the same motor equipped with a GT-40. Though 25 extra horsepower is nothing to sneeze at, the extra power was only available after 5500 rpm. Up to 5550 rpm, the modified GT-40 showed some pretty impressive gains from 3300 rpm all the way to 5550 rpm. Time and time again, the GT-40 continues to impress, though the TFS R intake clearly made more top-end power on this high-revving 347.

GT-40 Vs. Holley Systemax II
The Holley SysteMax bested the GT-40 by 5250 rpm, much earlier than the TFS R intake. Though the Holley offered a better torque curve, the additional torque production did not cost any top-end power. The Holley was only down by 1 hp compared to the TFS R intake. Like the TFS R, the Holley was down substantially to the GT-40 in the low and mid-range.

347 Test Motor Specs
•Block - 2-bolt 5.0
•Crank - Cast 3.40-inch 347-Coast High Performance
•Rods - 5.40-in. Steel H-Beam- (CHP)
•Pistons - Forged 10.5:1 5.0 Probe (11.5:1 with milled heads)
•Cam - XE 292R (Comp Cams)
•Lift - .621 in, .627 ex (.016, .018 lash)
•Duration - 254 in, 260 ex
•Lobe Center - 110
•Heads - AFR 185 (CNC ported & milled)
•Valves - 2.02-in, 1.60-ex
•Rockers - Comp Cams 1.6 ratio roller
•Intake - GT-40
•Throttle Body - 70 mm Accufab MAF - 77mm ProM (36 lb. calibration)
•Computer - EEC IV plus Ford Racing Extender
•Injectors - 36 lbs.-hr.
•Ignition - MSDHeaders - 13/4-inch full length Hooker
•Water Pump - Electric CSI
•Timing - 34* Total

TEST 1 -- GT-40 Intake-Baseline
•Peak Power Numbers: GT-40 Intake CHP 347-AFR heads & XE292R cam
•Peak Horsepower-GT-40 450 hp @ 6600 rpm
•Peak Torque-GT-40 447 lbs.-ft. @ 4700 rpm

EngineGT-40
RPMHPHPTqTq
3000NANA/td>
3200NANA
3400263406
3600289421
3800314434
{{{4000}}}334438
4200351439
4400370442
4600388444
4800408447
{{{5000}}}424445
5200433437
5400438427
5600441414
5800438396
{{{6000}}}434379
6200437371
6400447367
6600450358

TFS R INTake
Peak Power Numbers: GT-40 Intake vs. TFS RCHP 347-AFR heads & XE292R cam

EngineGT-40HolleyGT-40Holley
RPMHPHPTqTq
3000NA201NA351
3200NA218NA358
3400263242406374
3600289268421391
3800314288434399
4000334307438403
4200351330439412
4400370351442419
4600389368444420
4800408384447420
5000424400445420
5200433416437420
5400439430427418
5600441446414418
5800438458396414
6000434466379408
6200437472371400
6400447475367390
6600450470358374

Peak Horsepower -- GT-40 450 hp @ 6600 rpm * Peak Horsepower -- TFS R 475 hp @ 6500 rpm * Peak Torque -- GT-40 447 lbs.-ft. @ 4700 rpm * Peak Torque -- TFS R 422 lbs.-ft. @ 5100 rpm

GT-40 vs. Edelbrock Victor 5.0
The graph comparison between the Edelbrock Victor 5.0 and the GT-40 looks a lot like the comparison between the TFS R and the GT-40. In fact, with the exception of the extra power produced by the Victor 5.0 available from 6400 rpm to 6700 rpm, the TFS R and Edelbrock traded blows all the way up the power band. Like the TFS R intake , the Victor 5.0 lost power compared to the GT-40 all the way up to 5550 rpm. At that point, the Edelbrock stormed away in terms of power production.

TFS R vs. Holley
Note the significant humps in the torque curve offered by the Holley manifold. The Holley bested the TFS intake all the way up to 6300 rpm, where the TFS manifold took the power lead by the smallest of margins.

Victor 5.0 vs. Holley
The story was repeated in a comparison between the Holley and the Edelbrock, though the differential was not quite as dramatic as with the TFS manifold. The Holley offered more power and torque throughout the range up to 6100 rpm, where the Edelbrock turned the tables to the tune of 13 hp at 6600 rpm. It is possible that the Edelbrock intake requires an even wilder motor combination to fully realize its potential.

Holley SysteMax II
•Peak Power Numbers: GT-40 Intake vs. Holley SysteMax II
•CHP 347-AFR heads & XE292R cam
•Peak Horsepower-GT-40 450 hp @ 6600 rpm
•Peak Horsepower-Holley 474 hp @ 6300 rpm
•Peak Torque-GT-40 447 lbs.-ft. @ 4700 rpm
•Peak Torque-Holley 436 lbs.-ft. @ 5300 rpm

EngineGT-40HolleyGT-40Holley
RPMHPHPTqTq
3000NANANANA
3200NA217NA356
3400263247406382
3600289269421393
3800314293434404
4000334319438419
4200351342439428
4400370354442422
4600389368444421
4800408389447425
5000424410445431
5200433431437436
5400439445427433
5600441457414428
5800438466396422
6000434469379411
6200437472371399
6400447473367388
6600450468358372

EDELBROCK victor 5.0

The Edelbrock Victor 5.0 posted the highest peak horsepower numbers, generating 481 hp at 6600 rpm. The 426 lbs.-ft. placed it above the TFS R but below the Holley in terms of maximum torque output.

•CHP 347-AFR heads & XE292R cam
•Peak Horsepower-GT-40 450 hp @ 6600 rpm
•Peak Horsepower-Victor 5.0 481 hp @ 6600 rpm
•Peak Torque-GT-40 447 lbs.-ft. @ 4700 rpm
•Peak Torque-Victor 5.0 426 lbs.-ft. @ 4900 rpm

EngineGT-40VictorGT-40Victor
RPMHPHPTqTq
3000NA192NA336
3200NA209NA342
3400263238406367
3600289264421385
3800314288434397
4000334311338408
4200351327439409
4400370345442411
4600389366444417
4800408386447422
5000424404445424
5200433419437423
5400439433427421
5600441444414416
5800438456396413
6000434464379407
6200437474371401
6400447478367392
6600450481358382