20 Popular LS1 Intake Manifolds Dyno Tested

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Don’t Even Think About Swapping Your LS Intake Until You Read This

Is an intake manifold an important part of a performance LS build? The answer is, obviously, yes. One need only look at the peak power difference between the least and most powerful intakes in this shootout was more than 60 hp. Imagine that, an intake swap that yielded 60 extra horsepower, but that isn’t the whole story. While peak power gains offer enticing Internet banter, changes in the entire power curve are the real story. That is why we are also including average power production from 3,000 to 7,000 rpm, torque production at 4,000 rpm, cost, throttle opening, runner length, composition, and even What We Liked and might change on each design. In short, this was the most extensive LS intake manifold test ever devised.

Though we know you have already skipped ahead to the data, there are two important points to consider. The first is that no intake test, including this LS extravaganza, is absolute. Intake manifolds are combination specific, meaning that the ideal intake for an 8,000-rpm stroker combination would be different than one designed for a stock 4.8L truck motor. If you’re looking for the “best” single intake on the market for every application—such an animal does not exist. This test should provide you info on what design might work best for your combo.

The Test Engine
Speaking of combos, our test motor was built to simulate your basic hot street-strip setup. The iron-block 6.0L featured a stock block and crank mixed with Carillo rods and CP flat-top pistons. The Comp 469 cam offered a 0.617/0.624-inch lift split, a 231/247-degree duration split and 113-degree LSA. Topping the 6.0L was a set of AFR LSX 230 V2 heads. The various intakes were run with no less than eight different fuel rails, seven different throttle-bodies, and three different style injectors. Naturally, air/fuel, timing, and temperatures remained constant during testing. Check out the results to see how your favorite or future favorite fared.

Stock LS1

eBay Price: $155
Construction: Composite
Runner Length: 11.0 in
Throttle Opening: 2.960 in
Throttle-Body Size Tested: Accufab 78mm
Fuel Rail: Wilson billet
Injectors: Holley 75 lb
Peak Power: 535 hp at 6,900 rpm
Peak Torque: 468 lb-ft at 5,100 rpm
Ave HP (3,000–7,000): 418.9 hp
Ave TQ (3,000–7,000): 438.6 lb-ft
TQ at 4,000 RPM: 446.4 lb-ft

What We Like: OEM quality and fitment
What We Don’t: Least powerful of all the factory intakes

Our testing began with the LS intake that started it all, the LS1. Least powerful of all the factory offerings, the LS1 definitely limited the power output of our 6.0L test motor. Equipped with the factory LS1 intake and Accufab 78mm throttle-body, the 6.0L produced peak numbers of 535 hp and 468 lb-ft of torque. This curve was to serve as the baseline for the remainder of the LS intakes.

Stock LS6

eBay Price: $195
Construction: Composite
Runner Length: 11.0 in
Throttle Opening: 2.960 in
Throttle-Body Size Tested: Accufab 78mm
Fuel Rail: Wilson Billet
Injectors: Holley 75 lb
Peak Power: 557 hp at 7,000 rpm
Peak Torque: 483 lb-ft at 5,000 rpm
Ave HP (3,000–7,000): 432.0 hp
Ave TQ (3,000–7,000): 450.9 lb-ft
TQ at 4,000 RPM: 454.3 lb-ft

What We Like: Factory fitment and better power than LS1
What We Don’t: Limited availability and elevated price

First up was the LS6 intake. Designed as a factory upgrade for the LS1, the LS6 intake once again proved its reputation by significantly improving the power of our 6.0L. Compared to the LS1, the LS6 offered an additional 22 hp and 15 lb-ft of torque. The LS6 is harder to find and slightly more expensive than the LS1, but the power gains are worth it.

Stock Truck

eBay Price: $80
Construction: Composite
Runner Length: 11.0 in
Throttle Opening: 2.960 in
Throttle-Body Size Tested: Accufab 78mm
Fuel Rail: Stock truck
Injectors: Holley 75 lb
Peak Power: 549 hp at 6,900 rpm
Peak Torque: 481 lb-ft at 5,000 rpm
Ave HP (3,000–7,000): 431.2 hp
Ave TQ (3,000–7,000): 450.8 lb-ft
TQ at 4,000 RPM: 454.5 lb-ft

What We Like: Availability and performance
What We Don’t: Ugly

Naturally, we tested the factory truck intake, as GM made literally millions of trucks equipped with either the 4.8L, 5.3L, or 6.0L—all sharing the same intake. The popularity and price of 4.8L and 5.3L swaps means there are plenty of truck intakes to be had. Though the most affordable of all the factory offerings, the truck intake easily outperformed the LS1 by 14 hp and excelled at torque production, nearly matching the performance-oriented LS6. The average horsepower and torque production for the truck intake bested the LS1 and matched the high-powered LS6, making the truck intake a good choice for many applications.

Stock Trail Blazer SS

eBay Price: $210
Construction: Composite
Runner Length: 9.5 in
Throttle Opening: 3.45 in
Throttle-Body Size Tested: FAST 90 mm
Fuel Rail: FAST (modified mounts)
Injectors: Holley 75 lb
Peak Power: 562 hp at 7,000 rpm
Peak Torque: 497 lb-ft at 5,000 rpm
Ave HP (3,000–7,000): 444.4 hp
Ave TQ (3,000–7,000): 464.6 lb-ft
TQ at 4,000 RPM: 469.5 lb-ft

What We Like: Bigger throttle opening and best overall factory performer
What We Don’t: Limited availability and even more expensive than the LS6

Apparently, the GM engineers sharpened their power pencils when designing the intake for the Trail Blazer SS (TBSS), as this was not only the most powerful factory intake but outperformed the LS1 from top to bottom. Unlike the LS6 that matched the power of the LS1 down low (then took off), the TBSS intake offered more power and torque everywhere. By making more torque than the truck intake and more power than the LS6, the TBSS offered the best of both worlds.

Speedmaster

Retail Price: $220
Construction: Cast aluminum
Part Number: PCE-148.1007
Runner Length: 8.5 in
Throttle Opening: 3.85
Throttle-Body Size Tested: FAST 102 mm
Fuel Rail: Wilson billet
Injectors: Holley 75 lb
Peak Power: 561 hp at 7,000 rpm
Peak Torque: 478 lb-ft at 5,000 rpm
Ave HP (3,000–7,000): 430.2 hp
Ave TQ (3,000–7,000): 449.5 lb-ft
TQ at 4,000 RPM: 453.9 lb-ft

What We Like: Low cost
What We Don’t: Like to see larger throttle opening and longer runners

Stepping into aftermarket cast-aluminum intake offerings, the Speedmaster intake offered shorter (and larger) runners than the LS1 as well as a larger throttle opening. The power gains were most consistent at the top of the rev range, but like the factory truck manifold, the Speedmaster even offered additional torque down low. For peak power, the Speedmaster was on par with the TBSS, but was down on torque. Something we really liked about the Speedmaster unit was, at $220, it could be purchased for little more than the factory TBSS intake. The cost and power made it a desirable alternative to the factory LS1 intake.

Weiand

Retail Price: $519
Construction: Cast aluminum
Part Number: 300-111
Runner Length: 11.5 in
Throttle Opening: 3.030
Throttle-Body Size Tested: Accufab 78mm
Fuel Rail: Wilson billet
Injectors: Holley 75 lb
Peak Power: 566 hp at 6,900 rpm
Peak Torque: 487 lb-ft at 4,900 rpm
Ave HP (3,000–7,000): 438.3 hp
Ave TQ (3,000–7,000): 457.7 lb-ft
TQ at 4,000 RPM: 463.7 lb-ft

What We Like: Ease of installation
What We Don’t: Small throttle opening and weight of cast-aluminum manifolds vs. composite

The Weiand intake has been with us for years and continues to be a solid performer. The Weiand handily outperformed not only the LS1 but all of the factory manifolds, including the Trail Blazer SS. Like the Speedmaster, the torque was down compared to the Trail Blazer SS manifold, but we soon discovered that only two other intakes would best the peak torque offered by the impressive Trail Blazer SS. An extra 31 hp more than the LS1 is a hefty chunk of power and shows just how limiting the factory manifold can be on a modified 6.0L.

BBK SSI

Retail Price: $499
Construction: Cast aluminum
Part Number: 5004
Runner Length: 10.0 in
Throttle Opening: 3.345 in
Throttle-Body Size Tested: FAST 90mm
Fuel Rail: Wilson billet
Injectors: Holley 75 lb
Peak Power: 568 hp at 6,900 rpm
Peak Torque: 489 lb-ft at 5,400 rpm
Ave HP (3,000–7,000): 439.2 hp
Ave TQ (3,000–7,000): 458.2 lb-ft
TQ at 4,000 RPM: 462.0 lb-ft

What We Like: Performance
What We Don’t: Weight and flexible bottom cover

The BBK was the final cast-aluminum, long-runner intake we tested, and it performed very well. With peak numbers of 568 hp and 489 lb-ft of torque, the SSI intake offered a solid combination. The BBK intake also looked the part, though a splash of black would really wake it up visually. Compared to the LS1, the SSI intake offered slightly more torque down low and shined as revs increased.

Holley Mid Rise EFI

Retail Price: $647
Construction: Cast aluminum
Part Number: 300-126
Runner Length: 5.00 in
Throttle Opening: 3.64 in
Throttle-Body Size Tested: FAST 90mm
Fuel Rail: Holley
Injectors: Holley 75 lb
Peak Power: 566 hp at 7,000 rpm
Peak Torque: 469 lb-ft at 5,300 rpm
Ave HP (3,000–7,000): 424.9 hp
Ave TQ (3,000–7,000): 442.4 lb-ft
TQ at 4,000 RPM: 441.2 lb-ft

What We Like: Versatility and better hood clearance than Hi Ram
What We Don’t: Less power than Hi Ram

Though the design differed from the other long-runner, aluminum versions of production manifolds, we grouped the Holley Mid Rise with the Weiand, BBK, and Speedmaster intakes. The Mid Rise offered improved hood clearance compared to the Hi Ram, but the power gains were nowhere near as significant. Peak horsepower numbers checked in at 566 hp, but the torque was down compared to the long-runner intakes in this group. Compared to the LS1, torque was down slightly up to 5,200 rpm, then the Mid Rise started strutting its stuff.

FAST/Wilson LSX

eBay Price: $525
Construction: Composite
Runner Length: 12.0 in
Throttle Opening: 3.060 in
Throttle-Body Size Tested: FAST 78mm
Fuel Rail: Wilson billet
Injectors: Holley 75 lb
Peak Power: 571 hp at 7,000 rpm
Peak Torque: 490 lb-ft at 5,600 rpm
Ave HP (3,000–7,000): 438.5 hp
Ave TQ (3,000–7,000): 457.0 lb-ft
TQ at 4,000 RPM: 455.1 lb-ft

What We Like: The originator with plenty of performance
What We Don’t: Small throttle opening and now takes a backseat to the LSXR versions

We had this original FAST/Wilson LSX intake laying around the shop, so we included it in the test. This intake started the composite revolution, and we’d like to know how many were sold to LS enthusiasts before they upgraded to the LSXR versions. This intake has never failed to impress with power gains over the LS1 (and LS6). Despite sharing the same throttle opening, this early FAST offered an additional 36 hp more than the LS1 and 14 hp more than the LS6.

FAST LSXR 102mm

Retail Price: $951
Construction: Composite
Part Number: 146302
Runner Length: 10.5 in
Throttle Opening: 3.970 in
Throttle-Body Size Tested: FAST 102mm
Fuel Rail: FASAT
Injectors: FAST 75 lb
Peak Power: 591 hp at 6,900 rpm
Peak Torque: 505 lb-ft at 5,700 rpm
Ave HP (3,000–7,000): 450.0 hp
Ave TQ (3,000–7,000): 468.4 lb-ft
TQ at 4,000 RPM: 466.4 lb-ft

What We Like: Impressive overall power and torque curves
What We Don’t: Cost

Things got serious when we installed the 102mm FAST LSXR (it also offers a 92mm version that would be about 10 to 12hp down). Equipped with the LSXR, the modified 6.0L produced 591 hp and 505 lb-ft of torque. The FAST intake offered impressive peak power and the highest torque production of any of the intakes tested. Though some of the shorter runner intakes made slightly more peak power, it is hard to beat this long-runner design for average power production.

FAST LSXRT 102mm

Retail Price: $999
Construction: Composite
Part Number: 146602
Runner Length: 10.5 in
Throttle Opening: 3.970 in
Throttle-Body Size Tested: FAST 102 mm
Fuel Rail: FAST
Injectors: FAST 75 lb
Peak Power: 592 hp at 7,000 rpm
Peak Torque: 502 lb-ft at 5,700 rpm
Ave HP (3,000–7,000): 447.8 hp
Ave TQ (3,000–7,000): 466.0 lb-ft
TQ at 4,000 RPM: 464.3 lb-ft

What We Like: Design improves entry into cylinder heads to increase power
What We Don’t: Height of intake may limit fitment

Theoretically, the straight runners in the 102mm LSXRT should improve power production, but the RT version managed to squeak past the (low profile) LSXR by just 1 hp. The two traded torque production, with the LSXR coming out on top 505 lb-ft to 502 lb-ft for the RT. Still, the LSXRT offered an impressive 57 hp and 34 lb-ft of torque more than the LS1.

MSD Atomic Airforce

Retail Price: $949
Construction: Composite
Part Number: 2702
Runner Length: 8.5 in
Throttle Opening: 4.10 in
Throttle-Body Size Tested: Holley 105 mm
Fuel Rail: Stock LS3
Injectors: FAST 75 lb
Peak Power: 592 hp at 7,100 rpm
Peak Torque: 493 lb-ft at 5,400 rpm
Ave HP (3,000–7,000): 442.4 hp
Ave TQ (3,000–7,000): 460.0 lb-ft
TQ at 4,000 RPM: 454.7 lb-ft

What We Like: Another powerful composite LS manifold to choose from
What We Don’t: Slightly heavier than factory composites

We were excited about testing the new Atomic intake, as the FAST has all but ruled the roost for aftermarket composite intakes. The new Airforce intake demonstrated that the MSD designers brought their A game. Equipped with the new Atomic, the 6.0L pumped out 592 hp and 493 lb-ft of torque. With these results, obviously, the Atomic must be viewed as a serious player. Now we need to see how much boost it will take.

Symbol Performance

Retail Price: $700
Construction: Fabricated aluminum
Part Number: 81001
Runner Length: 5.5 in
Throttle Opening: 4.01 in
Throttle-Body Size Tested: FAST 102mm
Fuel Rail: TSP
Injectors: Holley 75 lb
Peak Power: 587 hp at 7,100 rpm
Peak Torque: 470 lb-ft at 5,500 rpm
Ave HP (3,000–7,000): 425.6 hp
Ave TQ (3,000–7,000): 442.8 lb-ft
TQ at 4,000 RPM: 439.5 lb-ft

What We Like: Impressive visual statement and top-end power
What We Don’t: Fuel rails that use pipe fittings

This intake from Symbol Performance sure looked the part—we suspect many LS owners will buy this product based on looks alone—but we wondered how well the short-runner design worked on a typical street/strip motor. Like the single-plane, carbureted intakes we tested, this piece offered short intake runners designed to promote power production higher in the rev range, and that is exactly what it did. The short runner lost out in torque production to the LS1 at less than 5,300 rpm, then pulled away strongly thereafter, peaking at 587 hp (a gain of 52 hp).

Edelbrock Pro-Flow

Retail Price: $587
Construction: Cast aluminum
Part Number: 71393
Runner Length: 6.25 in
Throttle Opening: 3.55 in
Throttle-Body Size Tested: FAST 90mm (and Edelbrock 90mm)
Fuel Rail: Edelbrock
Injectors: Holley 75 lb
Peak Power: 593 hp at 7,000 rpm
Peak Torque: 474 lb-ft at 5,700 rpm
Ave HP (3,000–7,000): 431.6 hp
Ave TQ (3,000–7,000): 448.3 lb-ft
TQ at 4,000 RPM: 438.7 lb-ft

What We Like: Looks/performs great and casting ensures no boost/vacuum leaks
What We Don’t: Doesn’t use LS throttle-body pattern

The Edelbrock Pro-Flow shared the tunnel-ram design with the TSP and Holley Hi-Ram, but the runners were slightly longer than the TSP. The Edelbrock showed the effectiveness of this design by offering 593 hp (a gain of 58 hp) and 474 lb-ft of torque (up 6 lb-ft). Like the TSP, the Edelbrock was down compared to the LS1 below 4,700 rpm, but pulled away handily thereafter.

Holley Hi-Ram EFI

Retail Price: $724
Construction: Cast aluminum
Part Number: 300-123
Runner Length: 6.50 in
Throttle Opening: 4.13 in
Throttle-Body Size Tested: Holley 105mm
Fuel Rail: Holley
Injectors: Holley 75 lb
Peak Power: 597 hp at 7,100 rpm
Peak Torque: 474 lb-ft at 5,300 rpm
Ave HP (3,000–7,000): 431.4 hp
Ave TQ (3,000–7,000): 448.0 lb-ft
TQ at 4,000 RPM: 439.7 lb-ft

What We Like: Versatility and tunnel-ram design makes top-end power
What We Don’t: Like to see the attachment bolts for the lids come in from the top

The Hi-Ram was the horsepower king in this test, though by a scant 4 hp more than the Edelbrock Proflow (597 versus 593 hp). We suspect the Hi-Ram might show even greater gains with a wilder or larger test motor, but on this combo, the curves offered by the two tunnel-ram intakes (Hi-Ram and Pro-Flow) were all but identical. Like the others, the short-runner Hi-Ram traded torque below 4,700 rpm to the LS1, but motored away on the big end.

Holley Hi-Ram Carb

Retail Price: $635
Construction: Cast aluminum
Part Number: 300-115
Runner Length: 6.50 in
Carbs: Dual Holley 950 XPs
Peak Power: 586 hp at 7,100 rpm
Peak Torque: 475 lb-ft at 5,300 rpm
Ave HP (3,000–7,000): 433.3 hp*
Ave TQ (3,000–7,000): 446.0 lb-ft*
TQ at 4,000 RPM: 435.6 lb-ft

What We Like: Dual quads sticking through a hole in the hood attract attention
What We Don’t: Sometimes unwanted attention

Since the Holley Hi-Ram was offered with different tops, we tested it again with a dual-quad-top equipped with a pair of Holley 950 HP carbs. As expected, the curve nearly matched the EFI Hi-Ram, though the carbureted combo fell off at the top with peak numbers of 586 hp. Torque was up by 1 lb-ft with a peak of 475 lb-ft. The carbureted Hi-Ram showed once again that short runners excel at power production higher in the rev range than the factory LS1.

Holley Mid-Rise Carb

Retail Price: $321
Construction: Cast aluminum
Part Number: 300-120
Runner Length: 5.00 in
Carbs: Dual 600-cfm 4160
Peak Power: 538 hp at 6,900 rpm
Peak Torque: 465 lb-ft at 5,200 rpm
Ave HP (3,000–7,000): 419.0 hp
Ave TQ (3,000–7,000): 438.3 lb-ft
TQ at 4,000 RPM: 450.1 lb-ft

What We Like: Perfect for dual-quad LS swap
What We Don’t: 4160 carbs limit tuning

We also ran the Holley Mid-Rise in carbureted trim, though the dual-carb Mid-Rise was a more significant change in the intake design than the simple lid swap on the Hi-Ram. The Mid Rise required an intermediate section between the dual-quad lower and lid, which extended the runners slightly on the EFI version. The dual-quad-carbureted intake was run with a pair of 4160 carbs that lacked secondary metering blocks for jetting. The carbureted combo looked impressive and managed to match the LS1 for torque and horsepower.

Edelbrock Performer RPM

Retail Price: $299
Construction: Cast aluminum
Part Number: 71187
Design: Dual Plane
Runner Length(s): 6.0/8.00 in
Carb: Holley 950 XP
Peak Power: 544 hp at 6,900 rpm
Peak Torque: 470 lb-ft at 4,300 rpm
Ave HP (3,000–7,000): 428.7 hp*
Ave TQ (3,000–7,000): 446.6 lb-ft*
TQ at 4,000 RPM: 466.6 lb-ft

What We Like: Torquey nature of dual plane
What We Don’t: Loses out on the top end compared to single plane

The dual-plane Performer RPM showed its torquey nature by bettering the long-runner LS1 at less than 4,600 rpm. The dual-plane also offered more power at speeds of more than 6,300 rpm, but the LS1 was slightly better between those two extremes. This intake combo showed there was plenty of power for swap candidates who elect to run their LS with carburetion.

Edelbrock Victor Jr.

Retail Price: $370
Construction: Cast aluminum
Part Number: 28457
Design: Single plane
Runner Length(s): 4.5/7.50 in
Carb: Holley 950 XP
Peak Power: 552 hp at 7,000 rpm
Peak Torque: 463 lb-ft at 5,200 rpm
Ave HP (3,000–7,000): 413.4 hp
Ave TQ (3,000–7,000): 429.6 lb-ft
TQ at 4,000 RPM: 426.6 lb-ft

What We Like: Simplicity of carburetion
What We Don’t: Loss of torque inherent in single-plane design

As expected, the single-plane Victor Jr. offered more peak power than the LS1, but the downside was that (unlike the dual-plane) power production suffered below 5,500 rpm.
Like the tunnel-ram intakes, the single-plane design featured short runners, but where the tunnel-ram intakes offered the same runner length for all eight cylinders (for even power production), the single-plane featured four long(er) and four short(er) runners. This optimized power production from one set of four cylinders at a different rpm than the other.

Holley Single Plane

Retail Price: $252
Construction: Cast aluminum
Part Number: 300-132
Design: Single plane
Runner Length(s): 5.0/7.50 in
Carb: Holley 950 XP
Peak Power: 549 hp at 7,000 rpm
Peak Torque: 466 lb-ft at 5,500 rpm
Ave HP (3,000–7,000): 417.3 hp
Ave TQ (3,000–7,000): 436.0 lb-ft
TQ at 4,000 RPM: 438.7 lb-ft

What We Like: Offered good torque for a single plane
What We Don’t: Still typical trade-off in low speed for top-end power

Though similar in design to the Victor Jr., the Holley single-plane intake offered slightly better torque than the Edelbrock, but slightly less peak power. The question now is would you trade the extra 24 lb-ft down low for a loss of 3 hp at the top?

Results:
1st Place –
2nd Place –
3rd Place –

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