New Products / Parts

How to Choose the Right Pro LS Cam for Your Application

 
Summit-Racing-Pro-LS-Camshaft

(Image/Summit Racing)

Summit Racing Equipment has a new line of camshafts for LS and LS-based Vortec truck engines which consists of 10 different cam profiles for various performance applications.

The Summit Racing Pro LS Camshafts lineup includes:

  • 4 truck cam profiles
  • 3 automotive cam profiles
  • 2 LS3 rectangle-port specific profiles
  • 1 turbo cam profile

Summit Racing-brand parts are designed to be budget-friendly alternatives to other options without sacrificing quality and performance.

Want to see how these cams are made? Check out this tour of the factory making the Pro LS Camshafts.

The new Summit Racing Pro LS Camshafts are precision-machined from high-quality U.S. steel, and are designed to be easy on your valvetrain and run with lower-cost components, yet remain stable to over 7,000 rpm with a good valve spring kit.

So, if you’re doing a cam swap on a Gen. 3 or Gen. 4 LS or Vortec engine, you’re probably going to like these Summit Racing Pro LS camshafts.

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How to Pick the Right Pro LS Cam for Your Application

Cams are generally listed by duration, lobe separation, and advance. This muddies the waters and can compromise performance. Summit Racing Pro LS cams are designed with the specific timing events required by each application. From Stage 1 to Stage 4, you’ll find these timing events in exacting increments. This ensures repeatable performance and distinct behaviors.

For more valve event event theory read:

Important note: Summit Racing Pro LS Camshafts are not legal for use in California or other states with similar laws/regulations. Please check your state and/or local laws/regulations.

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Summit Racing Pro LS cams listed in this format:

Part NumberCamshaft DescriptionDuration
at .050"
Lobe
Separation
AdvanceLift
(1.7 Rocker)
Basic Operating
Range
IVO
at .050"
IVC
at .050"
EVO
at .050"
EVC
at .050"
Overlap
at .050"

 

Need a refresher on the valve events? Here they are in order of importance.

  • IVC=Intake Valve Closing. This event has the most control over the operating range.
  • IVO=Intake Valve Opening. This event has the most control over idle quality.
  • EVC=Exhaust Valve Closing. This event, in conjunction with IVO, creates overlap. It generally hurts low rpm performance, but is increasingly helpful at peak torque and above.
  • EVO=Exhaust Valve Opening. This is a compromise. Pressure on the piston before bottom dead center (BDC) helps, but works against you after BDC on the exhaust stroke.

Summit Racing Pro LS cams take the guesswork out of choosing the perfect cam.

Do you want to know what your engine will idle like? Look in the intake valve opening column. Want to know the rpm range? Look at the intake valve closing column..

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Summit Racing Pro LS Cams Downloadable Spec Chart

Detailed spec charts for every Pro LS Camshaft are listed in the continuing story below.

Here are those same specs in a single downloadable PDF:

Summit Racing Pro LS Cams Spec Sheet

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Summit Racing Pro LS Truck Camshafts

Pro LS Truck cams are designed to make power where it’s needed. The truck cams have intake closing points between 36 and 41 degrees after bottom dead center (BDC) for maximum punch where the converter hits.

  • The Stage 1 and Stage 2 truck cams are designed to work well with the stock converter.
  • The Stage 3 truck cam works great with a 2,500 stall.
  • The Stage 4 truck cam makes great power with a killer idle. It hits hard at 2,800-3,000 rpm –and keeps pulling through 6,800 rpm.

Idle quality is important and your tuner will find these cams are easy to work with. They won’t lug or surge, and are designed to maintain part-throttle efficiency. You can get the idle you want simply by raising or lowering the idle speed a bit.

Next, let’s talk about valve lift and the springs that match.

  • The Stage 1 truck cam is designed to work with the original springs.
  • The Stage 2 truck cam will too, but Summit Racing recommends LS6 springs to extend the rev range.
  • The Stage 3 and 4 truck cams are also designed around the LS6 springs.

Why LS6 springs? The 405 horsepower LS6 had .555 in. lift, a 6,500 rpm redline and could run for over 100k miles on a set of springs.

Summit Racing Pro LS/Vortec Truck Cams, Gen. 3 & 4

Part NumberCamshaft DescriptionDuration
at .050"
Lobe
Separation
AdvanceLift
(1.7:1 Rocker)
Basic Operating
Range
IVO*
at .050"
IVC*
at .050"
EVO*
at .050"
EVC*
at .050"
Overlap
at .050"
SUM-8712Stage 1 drop-in LS Vortec truck209/2171121.500/.5002,000-6,000 rpm-63642-4-10
Notes: The Summit Racing Stage 1 drop-in truck cam is great for day-to-day drivability and produces incredible torque right off idle. Idle speed can be tuned for smooth idle or a noticeable lope. No springs required. It uses a state-of-the-art cam lobe design to pull strongly past 6,500 rpm even with stock springs.
SUM-8701Stage 2 LS Vortec truck218/2271122.523/.5242,200-6,200 rpm-139460-1
Notes: The Summit Racing Stage 2 drop-in truck cam is great for a driver and produces incredible torque right off idle. Idle speed can be tuned for smooth idle or a noticeable lope. No springs required, but LS6 springs are recommended. It uses a state-of-the-art cam lobe design to pull strongly past 6,000 rpm.
SUM-8713Stage 3 LS Vortec truck222/2311125.545/.5452,500-6,500 rpm43852-13
Notes: The Summit Racing Stage 3 truck cam is about the biggest cam you can get for a 5.3 that will still retain decent road manners. A 2,500 stall converter is recommended. It has a strong lopey idle. It uses state-of-the-art cam lobe designs to pull strongly from 2,500 to 6,500 rpm with LS6 springs.
SUM-8714Stage 4 LS Vortec truck226/2301124.545/.5453,000-6,800 rpm54151-14
Notes: The Summit Stage 4 truck cam is the meanest truck cam out there. 2,800-3,000 Converter recommended. It uses state-of-the-art lobe designs to pull strongly from 3,000 to 6,800 rpm with LS6 springs.
*IVC=Intake Valve Closing, IVO=Intake Valve Opening, EVC=Exhaust Valve Closing, EVO=Exhaust Valve Opening

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Summit Racing Pro LS Automotive Cams

Next, let’s talk about the Pro LS automotive cams. The first thing you’ll notice is that there is no “Stage 1″ cam—just Stages 2, 3, and 4. That’s because most people willing to go through the time and effort of a cam swap want to see a bigger performance gain from their efforts than a Stage 1 cam will typically provide.

Cars are lighter than trucks with deeper gears, more converter. They often run headers.

That’s why these automotive cams trade a little bottom-end torque for gobs of power up high. One way to think of this trade-off is “adding duration,” though, as previously discussed, Summit Racing is being more specific with the valve events.

The intake valve closing points range between 43 to 50 degrees after BDC. Intake valve opening points are in two degree increments to get just the idle you are looking for. More on this later.

  • The Stage 2 cam is powerful, yet retains its road manners.
  • The Stage 3 cam is more aggressive and works great in your weekend warrior.
  • The Stage 4 cam is a bruiser. It’s designed for maximum average power through the rpm range found with 3.45-3.70 gears.
  • The LS3 cams are designed for rectangle port cylinder heads. They’re also designed to clear the LS3’s true flat-top pistons with minimum hassle. The Stage 3 cam allows you to mill the heads for more compression. The Stage 4 LS3 cam is designed for un-milled heads. Both are stable to 7,000+ rpm with the lighter LS3 intake valves and quality spring packs.

The Summit Racing Pro LS cams have more lift for better breathing. The Stage 2 and 3 cams are compatible with commonly available .600 in. lift spring packages. The Stage 4 maximizes performance with .625 in. lift.

Summit Racing Pro LS3 Stage 3 and 4 cams have .625 in. lift as well. These cams will pull cleanly to 7,000+ rpm with as little as 150 pounds at the seat and 400 pounds of open spring pressure.

Summit Racing Pro LS Automobile Cams, Gen. 3 & 4

Part NumberCamshaft DescriptionDuration
at .050"
Lobe
Separation
AdvanceLift
(1.7:1 Rocker)
Basic Operating
Range
IVO*
at .050"
IVC*
at .050"
EVO*
at .050"
EVC*
at .050"
Overlap
at .050"
SUM-8707Stage 2 LS 226/2381133.600/.6003,000-7,000 rpm3435536
Notes: The Summit Racing Stage 2 LS cam is the biggest cam that retains friendly road manners. It has a steady lope and tunes well with a minimum of hassle. It uses state-of-the-art cam lobe designs to pull strongly to 7,000 rpm with as little as 150 lbs. of seat pressure.
SUM-8708Stage 3 LS 231/2421133.600/.6003,500-7,000 rpm54657510
Notes: The Summit Stage 3 LS cam is a great cam for a weekend warrior. It has a lopey idle, but tunes well with a minimum of hassle. It uses state-of-the-art lobe designs to pull strongly past 7,000 rpm with as little as 150 lbs. of seat pressure.
SUM-8709Stage 4 LS 237/2461133.625/.6053,500-7,000 rpm75059714
Notes: The Summit Racing Stage 4 LS cam is the ultimate track cam for a car or truck with the factory intake manifold design. It has a rowdy idle and will out-horsepower any cam in its range. It uses state-of-the-art cam lobe designs to pull strongly past 7,000 rpm with as little as 150 lbs. of seat pressure. It's the largest cam that fits LS3 with unmilled heads, but always check piston to valve clearance and degree if necessary.
SUM-8710Stage 3 LS3 230/2421133.625/.6053,500-7,000 rpm54556510
Notes: The Summit Stage 3 LS3 cam is designed to be the biggest drop in cam that allows the heads to be milled slightly. This gives a bump to the overall torque curve. It has a strong steady lope and will out-horsepower any cam in its range. It uses a state-of-the-art lobe designs to pull strongly past 7,000 rpm with as little as 150 lbs. of seat pressure.
SUM-8711Stage 4 LS3234/247113.53.5.625/.6053,750-7,000 rpm74760714
Notes: The Summit Racing Stage 4 LS3 cam is designed for maximum acceleration across the gear ratio spread found in track vehicles. Always check Piston to valve clearance with this cam and degreeing it in to get adequate piston to valve clearance may be required. It has a strong lope and uses state-of-the-art cam lobe designs to pull strongly past 7,000 rpm with as little as 150 lbs. of seat pressure.
*IVC=Intake Valve Closing, IVO=Intake Valve Opening, EVC=Exhaust Valve Closing, EVO=Exhaust Valve Opening

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Summit Racing Pro LS Turbo Camshaft

The Summit Racing Stage 2 turbo cam stands alone thanks to a totally unique design. The lobes are stable to 7,000+ RPM with .600 in. intake and .575 in. exhaust lift.

The exhaust lobes are a little less aggressive than the intake lobes. These less-aggressive lobes crack the exhaust valve open a little easier against high cylinder pressures, which takes stress off the valvetrain.

Because of higher turbine-inlet pressures seen on single turbo applications, overlap is reduced to prevent reversion.

Summit Racing Pro LS Turbo Cam, Gen. 3 & 4

Part NumberCamshaft DescriptionDuration
at .050"
Lobe
Separation
AdvanceLift
(1.7:1 Rocker)
Basic Operating
Range
IVO*
at .050"
IVC*
at .050"
EVO*
at .050"
EVC*
at .050"
Overlap
at .050"
SUM-8706Stage 2 LS Turbo226/2301134.600/.5753,000-7,000 rpm44252-22
Notes: The Summit Stage 2 Turbo cam is specifically developed for turbocharged applications. It will spool quickly and minimizes reversion caused by high turbine inlet pressures. It also works well as a high-lift version of the SUM-8714 Stage 4 truck cam. It has state-of-the-art lobe designs stable to well over 7,000 rpm with as little as 150 lbs. of seat pressure.
*IVC=Intake Valve Closing, IVO=Intake Valve Opening, EVC=Exhaust Valve Closing, EVO=Exhaust Valve Opening

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Summit-Racing-Pro-LS-Cam-Install-in-engine

Summit Racing is testing these camshafts in practical, real-world engine builds. (Image/Summit Racing)

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Sample Stock LS Cam Comparisons

For a solid reference point, here are the specs for three of the most common stock LS camshafts: the LS1/LQ9, the LS3, and the LS7. Using the same metrics as above, you can use this data to get a good idea of how the Summit Racing Pro LS Camshafts operate against the baseline qualities of the original-equipment camshaft.

Stock GM LS Camshaft Specs

Part NumberCamshaft DescriptionDuration
at .050"
Lobe
Separation
AdvanceLift
(1.7:1 Rocker)
Basic Operating
Range
IVO*
at .050"
IVC*
at .050"
EVO*
at .050"
EVC*
at .050"
Overlap
at .050"
12561721Stock LS1/LQ9196/2011161.467/.479Idle-5,500 rpm-173338-16-33
12623063Stock LS3204/211117-4.551/.525Idle-6,500 rpm-194339-8-27
12638426Stock LS7210/230120.5-3.593/.589Idle-7,000 rpm-114159-9-20
*IVC=Intake Valve Closing, IVO=Intake Valve Opening, EVC=Exhaust Valve Closing, EVO=Exhaust Valve Opening

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What Else You’ll Need to Run a Summit Racing Pro LS Cam

The great thing about the Pro LS cams is that they are designed to work with proven, off-the-shelf components.

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Stack-of-Summit-Racing-Pro-LS-Cams

To ensure you don’t have to wait on your cam, Summit Racing is keeping plenty of stock on-hand. (Image/Summit Racing)

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Understanding the Importance of Valve Timing Events

Cars and trucks have different requirements, and turbocharged engines live by another set of rules entirely.

Yet another difference is how a larger displacement engine will soak up a bigger cam and maintain a smoother idle. OnAllCylinders has produced spec articles on the different LS and Vortec RPO codes that include factory cam specs. For comparison’s sake, the 4.8 and 5.3 engines started with cams around 191 at .050″ while the 6.0s were closer to 196 at .050″. Automotive cams had a larger range. From as small as 196 at .050″ in a 5.7L LS1 up to 210 at .050″ with the 7.0L LS7. We’ve included this information in the tables above to illustrate the differences.

Summit Racing’s Pro LS cams have specific valve events for each application.

In order of importance, let’s look at the four valve timing events.

  • Intake closing. This takes advantage of intake and exhaust manifold tuning and velocity. The truck cams close as early as 36 (SUM-8712) after bottom dead center (ABDC) and range up to 41 ABDC. (SUM-8714). This will increase low end torque. The Stage 3 (SUM-8708) and Stage 4 (SUM-8709) cams for cars close between 45 and 50 degrees for more top end.
  • Intake opening. Opening earlier increases airflow on the downstroke, but the downside is reversion. Notice the Stage 1 cam (SUM-8712) and Stage 2 Truck cam (SUM-8701) open the intake valve after top dead center (TDC) for a smoother idle. The earlier we open the intake valve before TDC, the rougher the idle gets. The biggest cams (SUM-8709 and SUM-8711) open at 7 before top dead center (BTDC), which is about as early as possible without having to flycut pistons. This being said, valve drop varies between cylinder heads and you always need to verify piston-to-valve clearance.
  • Exhaust closing. The truck cams close before TDC to maximize part-throttle efficiency. The Stage 2 Turbo Cam (SUM-8706) does to, but for different reasons. It prevents high backpressure between the exhaust port and the turbo from flooding back into the cylinder on the intake stroke. The larger automotive cams close as late as 7 after top dead center (ATDC) because they typically run at higher rpm, with headers and a free-flowing exhaust.
  • Exhaust opening. The larger automotive cams open closer to 60 degrees BTDC. At high rpm, we have less time to exhaust the gasses so we open the valve sooner. This relieves pressure that works against crank rotation on at BDC on the exhaust stroke. The truck cams open between 42 and 51 degrees for better part-throttle efficiency. These cams maximize the time cylinder pressure is pushing on the piston before the exhaust stroke occurs.

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7 Comments

  1. Pingback: How A Camshaft is Made: A Tour of the Summit Pro LS Cams Factory - OnAllCylinders

  2. Travis Jones says:

    The lack of actual spring requirements for these cams is frustrating. You show two different LS spring kits, one Beehive, one dual spring. Are PAC 1218’s or Comp 26918-16’s enough for the Stage 3 Automotive cam? Having just bought this cam I’d like to know before I install it.

  3. OnAllCylinders says:

    Congratulations on your purchase. Summit Racing uses a few factors to determine the spring kit required. Solid Stem vs. Hollow Stem, Factory vs. Roller rocker, stock top end vs. Heads/Intake are a few examples that change the recommendation. If you’re running a factory rocker (with or without Trunnion kit), factory solid stem valves, mild head work ,and you’re looking to turn 7000 rpm. The Pac-1218 has 130 at the seat and 318 open and would be a little on the light side. You could shim a set of Comp 26918-16’s to a 1.750 installed height. This would net 143 lbs. at the seat and 367 lbs. open and would work well. Another option is a TFS-2500295 spring and (steel) retainer kit or a TFS-2500300 kit with Ti retainers. These hit 150 at the seat and 420 open without any shimming.

  4. Douglas Williams says:

    I have a 2007 LWB 4.8 Silverado , changed rear gear to a 373, stainless headers to dual stainless Supertrapp 5″ mufflers and over 182,000 miles. Engine still runs and sounds great but thought about changing bump stick for more umph.I reprogrammed the computer & trans. Don’t know what top end is past 125mph. Very stable and solid truck. All parts have come from Summit and only will use Summit Racing. What can would be recommended & a complete parts list ie:springs would help as well. Thanks guys !

  5. Erick Beck says:

    Looking for a mild grind cam for A 1962 , 261 cu Inch straight six . Any help here ?

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