Summitracing

Hello, the intake opening, intake closing, and exhaust opening points are identical to our SUM-8709 Stage 4 naturally aspirated cam. Due to the high turbine inlet backpressure of a single turbo, we've dialed back the exhaust closing point in direct relation to the intake opening to limit overlap. This is key to reducing reversion and keeping excess heat out of the cylinder and chamber. This cam unfortunately would not run well N/A versus our others. If you are looking for a cam that "gets you by" until the turbo is installed, the stage 3 turbo SUM-8716 would function fairly well. There are other cams we could recommend based on turbine flow and the potential for going twins. Those would be customs from your manufacturer of choice and we can dial them in to your specific needs.

Booster01

Hi,
I have a 2006 1500 flex fuel 5.3 mostly stock. I've swapped a 4l80e with a 24-2600 stall. I am running a 78/75. I am trying to decide which of the summit cams to run. I do not want to lose much drivability. I won't mind a little lope. I pull a camper a lot. Stay around 2800-3200 pretty consistently. I'm willing to run dual springs if necessary. I've been looking at the 8720. But you seem very helpful and wanted I to check your opinion.

Thank you in advance.

Mavn

iTrader: (3)

sum-8715

SLOW SEDAN

iTrader: (13)

That is a great all around cam, cruises nice but also went 9.3 on only 10lbs of boost in my manual car.

Booster01

Thank you for the recommendations guys. The 8715 has good torque range as well from all of your experience?

Summitracing

Booster01,

Thanks for checking in on the thread for a recommendation. We appreciate the nod for the Ghost cam from Mavn and Slow Sedan. We think the Ghost would be a great cam for this truck if it was more of a sport truck that didn't tow.

With you mentioning this truck is used to pull a camper often we would recommend the SUM-8720. It will have that torque you're looking for lower in the range with its 39* IVC compared to the 43* IVC of the Ghost cam. It will have a bit of an idle to it but be plenty easy to tune. In the event, you need to ring it out getting up an on-ramp the 8720 won't have a problem singing to 6,500+. You can keep it happy with PAC 1218 beehives which we carry through Trickflow as TFS-16918-16. If you're one for added insurance we have the Trickflow .660 lift duals TFS-2500286. We also have BTR BTC-SK001S0560BB dual springs that would work well with this cam.

We would recommend upgrading pushrods. Typically, we see 7.425" length work at this lift. Things vary so we always recommend measuring pushrod length before purchasing pushrods. If you don't have one already a pushrod length checker such as the TFS-9501 is a good tool to have. We would go with a minimum of a 5/16" Chromoly pushrod with a .080" wall thickness. You can typically find a set of these from popular brands for around $100. From there you can get into thicker wall and or larger diameter pushrods such as our HDR line.

It's in a 4.8 but check out this Richard Holdener video. It featured many aftermarket stage 2 cams including this 8720 and our 8706 turbo cam. Around the 16:30 mark is where our two cams are compared.


If you have any more questions feel free to reply to this post or shoot us a PM. We'll be happy to help.

Booster01

Thank you for the thorough and detailed response. It gives me a very clear direction to take. The cam is currently out of stock so I will keep an eye out for it. This will be the one I run with and I will run thicker pushrods and dual lift springs as you stated to be safer.

Booster01

Also, I have sent a pm with questions before I purchase.

Summitracing

Just wanted to update the thread that we got Booster01 setup with a SUM-8720-2-DLSTL cam combo. It was a pleasure working with you Booster01! If anyone else is lurking on the thread feel free to ask us about a cam for your combo. We'll be happy to help!

DavidBoren

How well would the 8717 cam work with your 120mm TB sheetmetal intake?

The cam's operating range is advertised as 3500-7200rpms, and the intake's at 2500-6800rpms... I am hoping the intake could be used to tune peak a little earlier, but still not choke the cam.

I want to size the turbo so that a bigger cam won't get anything out of the turbo, and a bigger turbo won't get anything more out of the 8717 cam... whatever that balancing point may be with a 6.0L LS and church port heads.

Thinking a single S480 should be just about right for taking a 6.0L to ~6,800rpms...

Summitracing

Hi David, 8717 would be a good match for that turbo but with a 6.0, you may even want to consider a SUM-8716 stage 3. This is going to light off things a little lower. The upper part of the RPM scale is based on how well the cam keeps the valvetrain happy at that 7000+ rpm. In other words, if the cam was N/A it might only make peak power at 6400 but would carry out well to 7200. The Turbo makes anything hang on a little longer. This stresses the valvetrain a bit but power is made and everything will remain happy with the lobe acceleration on these cams. The intake is a little of the same story. It's hard to state a range with them because at the end of the day, the runner length is still less than a truck intake for instance. It too is going to be very happy from 4500-7500+. We think stage three is going to give the best overall power curve and behavior for what you are trying to achieve. That being said, you will find that it will still want to rev and you are in good shape to do so.

hot98z28

I have an 02 z71 with all the best things from factory 3:73 gears locker diff etc. I put an lq9 with 243 heads and shorty headers and ss exhaust. This is a work truck that likes to play sometimes, how will the stage 1 fare?

Summitracing

Thanks for checking in on the thread for a recommendation. We saw your post on Mavn's thread also included your Camaro so we're responding to both here.

For the 02 Z71. The Ghost cam could work here. The added compression and 3:73 gears will help. We actually think there is a better option being that this is in a truck. Our stage 2 high lift truck cam SUM-8720R1. Specs on it are .600/.600, 218/227, 112+2. This is more suitable for a truck and stock torque converter. It draws the powerband down lower with its 39* IVC vs. the 43* IVC of the Ghost cam. The earlier we close the intake valve the lower the powerband will be. Pair this with some PAC 1218 beehives and it'll be happy to 6,500+ for when you're feeling sporty. We carry those springs through Trickflow as TFS-16918-16.

Regarding the Ghost cam for the 4th gen with the LS3. We have quite a few customers who've installed the Ghost cam in LS3 applications. If you're looking for something with a smooth idle and easy to tune the Ghost cam would be great for this application. It's no slouch either. It can put down some power and carries out well t 6,800+ with the TFS-16918-16 beehives. One thing we pride ourselves on with the PRO LS cams are the smooth lobes that take it easy on the valvetrain.

Make sure your valvetrain geometry is in check on the 4th gen. You can increase valvetrain stability with a good set of pushrods. There's the industry standard 5/16" with a .080" wall. Then from there, you can get into thicker walls or larger diameters. Check out our Pro LS HDR pushrods. Our 11/32" pushrods will have 25% less stress and 28% less deflection than a typical 5/16 x .080 wall Chromoly pushrod. These will also fit stock or aftermarket heads.

Thanks again for checking with us on a recommendation. Good luck with both of your projects.

JimsNovaLS

Can I get some thoughts on a Summit cam for my 5.7 ? The engine was rebuilt and has PRC stage 2.5 5.3 heads with springs for up to .650 lift, 11:1 compression and an ls6 intake. I have the engine in an early Nova with a 2004r trans and a 3200 convertor and 3.73 rear gears. It was used for street & strip but will now be street only. I had a TSP 233-239 on 112 lc, .600 lift cam. That's a little more than I want for street only. I'm looking at your 8715R1, 8713R1 & 8707R1. I'm worried the 8715 might be too stealthy, I want to hear the idle. All out acceleration is not of great concern and I would like half-decent fuel mileage. What would you recommend and why? Also, I have 7.400 pushrods now that TSP recommended since the heads were milled. Do you think they will be ok? Thank you.

SLOW SEDAN

iTrader: (13)

Is anything in stock at Summit anymore? Forged bottom end parts seem to be backordered 4+ months, some of the cams are 2+ months out.

Mavn

iTrader: (3)

8715. Is the ticket here

DualQuadDave

iTrader: (6)

A lot of shops are out of cam cores; saw Texas Speed posted similar. I blame the Democrats 1000%. Gas is also $3 a gallon all within months.

SLOW SEDAN

iTrader: (13)

Crazy it does seem a lot of people cant get castings, cores, trans parts. I wish it was $3, hell it went to $3.55 here almost instantly.

Summitracing

Thanks for checking in on the thread for a cam recommendation. As far as a well-balanced cam for power and good mileage we agree with Mavn. The Pro LS Auto stage 1 SUM-8715R1 "Ghost cam" is a great fit. Specs on it are .600/.575, 222/234, 115+3 with -2* of overlap. It can have a good idle to it with the idle speed turned down and a fairly open exhaust. There's plenty of idle videos of it here and Youtube. That cam has been used in about any combo imaginable in 4.8's to 6.2's. It would suit your combo very well and have great driveability.

Here's a sample video of the many videos out there on the Ghost cam. This is in an LS1.

Another option is the Pro LS Auto stage 2 SUM-8707R1that you mentioned. Specs on it are .600/.600, 226/238, 113+3 with 6* of overlap. It's a great in-between of your current cam and the 8715R1. It will have a bit more bark than the 8715R1 but with the added compression, converter, and gears it would be street-friendly. It would be an absolute joy in a combo like yours. It might have a little less fuel mileage than the Ghost cam but would be better than the current cam.

For a sample of the idle of the stage 2 check out the video below. That's in an LS6.

You could go with either cam and get plenty of enjoyment out of it. All while being street-friendly with your combo. Either will work with your springs. As far as pushrods. The 7.400" you have just might work. Things vary so we recommend verifying you get the proper amount of pre-load for your lifters before final assembly.

Summitracing

Date: 3-16-21 There are two parts to this. Actually closer to three.

1,) Company wide we have about 1600 vendors and many have had an issue since Covid. Manpower at U.S.A. factories is an issue and there area couple of reason for that- that we are all aware of.

2.) Pro LS cranks/Rods/Pistons. Cranks have been "ok". Pistons have been pretty good. We have more control over them being 100% made in USA and we've purchased MASSIVE quantities of them to keep them in stock for you guys. Rods are an issue. We've had the 6.125 rods on backorder for a while now. We are increasing our orders for those as well....drastically. We've been pressing the vendor HARD for these and they are making a large delivery very soon.

3.) Pro LS cams. We have a good problem. The good news is the cams ARE in stock despite what you may see on our website. The problem is people aren't finding the re-designed ones easily. Our lobe designer incorporated "a thing" into the Pro LS cams as a rolling change. It increases rpm by a couple hundred across the board while maintaining where the cam starts to come on.. We've changed the cam numbers to the "R1's" as in "revision 1". So SUM-8706 becomes SUM-8706R1. SUM-8715 becomes SUM-8715R1. Duration, LSA and Advance remain the same. Lift remains the same with the exception of two truck cams where we go from .545 to .550 lift. Three cams have had their exhaust durations change by less than one degree, but we "fixed" the cam card to reflect whether the number rounded up or rounded down more precisely. The characteristics you have come to grow and love are the same....just a bit better.

Continuous improvement is a good thing, but not without it's hassles. In this case, we can't "erase" an old part number off our website if someone enters it by name. SUM-8720 for instance. We are doing a redirect so 8720's will show 8720R1. Even though the cams say "Not Available", there is still a due date on them as a function of our system. We are investigating ways to fix this. There IS a huge notice saying "Not Available? No Problem! You can substitute to "X"" slightly below the part number, but a lot of people aren't scrolling down enough to see that or don't quite understand what is going on. We don't blame them. In the meantime, we are changing the descriptions to say "REPLACED BY SUM-*87XXR1" etc. to give the customer every opportunity for success.

If you guys have further input etc., we will do our best to incorporate them and rest assured we are pushing Very Hard to get parts back into stock for your builds. Best Regards, Summit Racing.

Example of how our website appears.: