(Image/Summit Racing)

The new Summit Pro LS camshafts have been a hit.

The new product line launched in July and quickly developed a following.

Just a quick recap: Summit Pro LS cams are made in the USA and ground on a Landis 3LB for excellent lobe quality. The lobes are quick, but not so overly aggressive as to be hard on the valvetrain. Another benefit is they’re stable at high rpm to extend the horsepower curve.

The lineup was strong to begin with, but people chimed in with great ideas for new cam profiles. The result? Two new Truck Swap cams and three new Turbo grinds for non-pollution controlled vehicles.

New Summit Pro LS Truck Swap Camshafts

Since its release, the new Summit Stage 1 Pro LS Truck Swap cam has been getting great reviews. It’s a .500 lift drop-in cam with 209/217 duration, 113 lobe separation, and is ground with one degree of advance. It sounds great and tunes easy. It was designed for strong mid-range power, but owners reported something else as well.

The newfound power meant their truck no longer had to downshift going up medium grades, which helped increase their fuel economy and got Summit’s product development team thinking.

“What about all those 5.3L junkyard engines being swapped into old Winnebago RVs or trucks hauling racecars?! Let’s design a cam specifically to boost torque just off-idle, throughout the mid-range and maintain fuel efficiency.”

The result is the new Pro LS Stage 1 Drop-in Truck Swap Torque/Efficiency version.

Specs are 205/217 duration with 112 degrees of lobe separation, two degrees of advance, and .500 lift.

The new cam is designed to have a hint of an idle, won’t require a spring swap, and increases torque everywhere through the rpm range.

So how does it differ from the SUM-8712 Stage 1?

The new SUM-8718 has a slightly smoother idle and won’t require a tune—although it’s always recommended since there are power gains there as well.

The intake valve closes three degrees earlier, which boosts low-end torque. The sooner the intake valve closes, the sooner compression can build.

Some of the Stage 1 Truck Swap cam owners also said “I love this cam… do you offer a higher lift version?” The answer is: Yes.

The new Stage 1 High-Lift Truck Swap cam has the exact same valve events as the original SUM-8712—but packs .550 lift—making it perfect for use with LS6 springs. Why LS6 springs? They’re rated for up to .570 lift and have more seat and open pressure to extend the powerband. They’re also a great value coming in around $75 and compatible with the original retainers and locks.

Summit Racing Pro LS/Vortec Truck Swap Cams

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-8718Stage 1 Truck Tq. Efficiency205/2171122.500/.500750-6,000 rpm-83342-5-12
The Summit Stage 1 Drop-in truck Tq. Efficiency cam produces outstanding torque right off idle and maintains efficiency. It makes much better torque and power across the entire RPM range. Idle speed can be tuned for smooth idle or a slight lope. No springs are required.
SUM-8712Stage 1 drop-in LS Vortec truck209/2171121.500/.5002,000-6,000 rpm-63642-4-10
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-8719Stage 1 Truck High-lift209/2171121.550/.5501,800-6,200 rpm-73641-4-10
The Summit Stage 1 High-Lift truck cam produces good torque off idle with very good mid-range and good top-end power. Idle speed can be tuned for a smooth idle or a noticable lope. The extra lift increases power and torque across the range. This cam pulls strongly past 6500 rpm with proven LS6 springs.
SUM-8701Stage 2 LS Vortec truck218/2271122.523/.5242,200-6,200 rpm-139460-1
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-8720Stage 2 Truck High-Lift218/2271122.600/.6002,200-6,500 rpm-139460-1
The Summit Stage 2 High-Lift truck cam makes great mid-range and top-end power. It’s the largest recommended with a stock converter. It has a noticeable lope depending on idle speed. It works well with TFS-16918-style beehive springs. Works well with nitrous or supercharger.
SUM-8713Stage 3 LS Vortec truck222/2311125.545/.5452,500-6,500 rpm43852-13
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
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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New Summit Pro LS Turbo Camshafts

One new cam is so versatile that it could be called a number of things. A Stage 1 Automotive Stealth cam, a Stage 1 Turbo cam, or be used as a Stage 3 .600 lift Truck cam. Summit compromised and called it the Pro LS Stage 1 Stealth Turbo cam. It has 222/233 duration, 115 lobe separation, and 3 degrees of advance and has .600/.575 lift. What makes it special? The intake opens one degree after top dead center (ATDC) and closes at 43 after bottom dead center (ABDC). The exhaust opens at 55 before bottom dead center (BBDC) and closes two degrees before TDC. This results in -3 degrees of overlap. It can be tuned to run smooth or you can drop the idle for a bit of lope.

The lack of overlap also makes it an excellent turbo cam.

How were the Stage 3 and Stage 4 turbo cams developed? Summit started with the Stage 3 and Stage 4 naturally aspirated cams. Those are designed to complement the factory intake manifold design’s powerband.

What changes is the exhaust lobe and timing. The exhaust lobe is a little milder to break open easier against high cylinder pressure which takes stress off the valvetrain. The closing points are designed to net two degrees of overlap with their respective intake opening points.

Why is this important?

Single turbo engines running through a full length exhaust may exhibit high levels of backpressure between the turbo and the engine.

This is further aggravated if the wastegates are routed back through the exhaust rather than being open directly to atmosphere. The backpressure ratio could be 2:1 or even 3:1, meaning 10 pounds of boost may have as much as 30 pounds of backpressure.

This sounds bad, and it IS!

The result is exhaust trying to push back into the cylinder and intake port. By closing the exhaust valve early, Summit Turbo cams prevent reversion.

[Want to learn more about this subject? Check out How a 4-Stroke Engine’s Piston Motion and Valve Events Interact.]

The new Stage 3 Pro LS Turbo cam has 231/234 duration, 115 lobe separation and 5 degrees of advance. Lift is .600/.575, so it’s compatible with common and affordable spring packages. The exhaust valve closes at three before top dead center (BTDC).

The Pro LS Stage 4 Turbo cam has 237/234 duration, 117 lobe separation and five degrees of advance. This makes it the only reverse-split cam in the lineup. Lift is again .600/.575 and the exhaust closing point changes to five degrees before TDC.

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-8715Stage 1 LS Turbo222/2331153.600/.5752,800-6,800-14355-2-3
The Summit Stage 1 Turbo cam is designed for single turbo applications and has a noticeable lope. It spools quickly and pulls hard through the mid-range and has good top-end. A 2500 rpm stall converter is recommended, but not required.
SUM-8706Stage 2 LS Turbo226/2301134.600/.5753,000-7,000 rpm44252-22
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.
SUM-8716Stage 3 LS Turbo231/2341155.600/.5753,000-7,000 rpm54657-32
The Summit Stage 3 Turbo cam has an unmistakable lope, yet is easily tuned. It makes excellent mid-range and top-end power. It spools quickly and it's designed to work well even with higher turbine inlet pressures found on single turbo applications. A 2800+ stall converter is recommended.
SUM-8717Stage 4 LS Turbo237/2341175.625/.6003,500-7,200 rpm75059-52
The Summit Stage 4 Turbo cam is designed for built engines and serious power levels. This reverse split design is ideal for a single turbo applications with T4 hotside and full length performance exhaust system. A 3500+ stall converter is recommended.
*IVC=Intake Valve Closing, IVO=Intake Valve Opening, EVC=Exhaust Valve Closing, EVO=Exhaust Valve Opening

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So there you have it. Summit has expanded its LS cam lineup and made it better.

The Summit Pro LS cam lineup also includes car-specific cam profiles. Here are those options and specs:

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-8715Stage 1 LS 222/2331153.600/.5752,800-6,800 rpm-14355-2-3
The Summit Stage 1 cam is designed to provide a stealthy idle yet strong power to 6,500 rpm. Idle can be raised or lowered for lope or smooth idle. It is the largest cam that works with a stock converter. It also works well with turbo, nitrous, and supercharged applications.
SUM-8707Stage 2 LS 226/2381133.600/.6003,000-7,000 rpm3435536
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
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
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
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
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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To learn more about how the Summit Pro LS cams are made, read How a Camshaft is Made: A Tour of the Summit Pro LS Cams Factory.

Keywords
camshaft tech, LS video, product profile, Summit Pro LS camshafts, Tech, Video
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Author: Brian Nutter

After a stint in the U.S. Air Force, Brian Nutter studied at the Houston, TX-based School of Automotive Machinists in 1997. The early part of his automotive career included working for engine builders Scott Shafiroff and C.J. Batten, followed by several years developing performance pistons at Wiseco Piston Co. Today, Brian develops performance parts for Summit Racing Equipment and is a regular OnAllCylinders contributor. For fun, he runs his 427-powered C5 Z06 in ECTA land-speed racing, at OPTIMA® street car events, and at a mix of autocross, drag racing, and track days.