The quick fix would be a set of PAC-1276X springs. Obviously, not a free fix, but it's as simple as a spring swap and not having to change over to a dual.

 

No I was asked if I got it figured out. So I decided to answer.

 

Don't forget that I did say this, and you have to wonder why I just deleted it.
This is not all based off this thread.

 

thanks, looking forward to the response

 

Not sure where summit sources it's valvetrain parts from. I didn't see the open and closed pressure spec for the springs on the product page? I had fears of similar problems in my build and contacted numerous manufacturers. None really had any knowledge of valvetrain dynamics, at least their sales teams didn't. Additionally, quality of parts form one batch to another can vary depending on their manufacturing process. It's possible even if springs have one spec, they aren't quite built to that spec, never hurts to validate when possible although can be a royal PITA. There's a lot that can go on with a valvetrain that may not be managed or even accounted for in the quality process or even thought of design phase, then promises are made by marketing in the specs. Long story short, I spoke with Roger Vinci a GOD of valvetrain dynamics IMO. He spent hours on phone with me, both helping me setup my build and specing it out. Then he built my parts in his shop. You didn't buy your parts from him, but maybe he could be a resource...

http://www.vincihiperformance.com/
sales@vincihighperformance.com

Additionally, sounds like you may already be doing this. Maybe you could grab some more PID(s) with your tuning software to quantify valve float. Torque (not sure how accurate on P59 PCM), RPM, MAP (sounds like you got that one), MAF (maybe reacts too slow), not sure what else. I know if you get valve float it'll show up on a dynamometer as torque curve becomes unstable (oscillates & tapers off early). May want to monitor fuel pressure and or AFR in case the pump is falling short of the demand.

 

@4thGenCamaroZ28,

We don’t have quite enough information but we'll try to help where we can.

Both the SUM-8706R1 turbo cam and the SUM-8707R1 N.A. cam use the same intake lobe. Turbo engines have enough air to peak higher, but valvetrain stability will be the same in either case. Is one engine N.A. and the other boosted? We don’t expect a truck intake on a 6.0 to peak at 6500 even with SUM-8707R1. However, power shouldn’t fall off a cliff with either the -1 Beehive kit or the more expensive -1DS Dual Spring kit.

In the description for both 8707R1 cam and spring kits, we state a basic 3000-7000 operating range. We state the -1 beehive kit as “pulling to 7K” and the -1DS duals “pulling strongly through 7k”. Both are true, but there are variables to contend with when talking about operating range.

Variables to Consider

1. Engine Displacement
2. Truck intake, car intake, and aftermarket short-runner
3. Pushrod rigidity
4. Lifters and oil viscosity
5. Light stock rockers versus heavy aluminum rollers
6. Valve weights
7. Combined valve/retainer weights
8. Cylinder head flow

The 95KPA at WOT is a concern. Can you tell us about the air intake setup on both engines? Any differences in the manifolds or heads on the engines along with the concerns above may help us hone in on the issue.

 

Can you elaborate on this?

1. One is bored over so one is a 364 and one is a 370
2. NBSS (TBSS) I thought these flow the best of all factory intakes?
3. Comp Cams .080 wall and BTR .080 wall 5/16", .098 preload on both engines.
4. One has Summit "LS7 Spec" lifters of an Eaton design, One has Real GM lifters. Both 5W40 Euro Mobil 1 with Motorcraft FL500S filter
5. Stock Rockers
6. Stock
7. Stock, one with beehive springs, one with dual springs.
8. Stock, One has 799's, one has 243's

According to people on this site it's not supposed to have atmospheric pressure at WOT. I know that's not true.

Exhaust, Both have identical headers. One has Summit S10 kit for a GEN 1 swap adapted to the LS. That kit is 2 1/2 to a 2 in 2 out muffler. (that is both banks use the same muffler.)
One has 2 1/2 true duals out to the bumper with Cherry Bomb Pro, Welded mufflers.
Same Model FTI converters,

 

We have three lifters. The SUM-HT214’s are Eaton design replacements. The SUM-HT215’s are Delphi Ls7’s used in SUM-HTLSKIT2 and the SUM-HT217’s are Morel 7717 used in SUM-HTLSKIT3. When you say genuine GM, is that genuine GM LS7 out of an original LS7? Also please confirm which engine has which.

When talking about intakes. An intake may flow enough for 7500 rpm but the runner length peaks at 6500. The TBSS isn’t designed for 7k operation (it’s still a truck) but if both engines are using the same intake, we can rule that out.

Is the low rpm engine the one with 2” mufflers? Are we reading this right? Trying to make good power through 2” mufflers isn’t going to work. 8706 has limited overlap (turbo cam) and 8707 has a bit more and overlap makes the cam more sensitive to backpressure. Testing backpressure in front of the mufflers with a zerk is a way to determine if they are a restriction. We want to see less than 1 psi total restriction. Stock can be 8lbs plus at WOT and redline.

Are you using the same tach to read rpm on both? Some tachs can be 1000 rpm optimistic.

Next steps. We think a trip to the dyno would be helpful. It will help you quantify and watch the curve. The following pic is an example of the larger 230 and 234 degree SUM-8710R1 and SUM-8711R1 cams. Both peak at sub 6500 on a stock L99 (headers and Magnaflow exhaust automatic 5th Gen Camaro) with its better flowing heads and shorter runner LS3 intake. See how the power drops as it heads to 7k but doesn't fall off a cliff. That is good valvetrain stability. This car shifts a little past 7k in the real world.

The lifters and mufflers jump out at us as the bigger differences than the springs, but it’s hard to tell unless it’s dyno’d. At this point, we don’t think the springs are the magic bullet. Let us know your thoughts.

 

Oh Really? Good to know (that's sarcasm)


[/QUOTE]
My 2002 Camaro SS had the lifters replaced under warranty in 2004, they are GM Standard (same as LS7's) I can dig out that invoice if you need the part number. They have 5,000 miles on them and I used them in one of these.

I never said anything was running 2" exhaust. I'll type this as clearly as I can (again) It has a Summit S-10 Gen 1 V8 swap exhaust kit that has dual 2 1/2" pipe to a muffler that has two 2 1/2" inlets and two 2 1/2" outlets. [/QUOTE]

I'm reading it off the tach readout on HP Tuners Scanner on my laptop.

You didn't understand the mufflers.
You used to call the HT214 lifters LS7 Spec, but now they're "replacements" and I'd assume not LS7 Spec anymore since you list others that are described as LS7 Spec.
So the lifters used to be LS7 spec, now they're "replacements" and now you're saying they seem to jump out as a problem (?) The Springs have a lower seat pressure and rate than what the cam description says it needs. When are the springs description going to change like the lifter description did? That jumps out at me as being a problem.

If you'd like you can tell me which parts you think are on the engine that doesn't rev.

At this point I see this going nowhere.

 

We wanted to let the community know that we've come to a resolution with @4thGenCamaroZ28 that both parties are happy with.

We're working out details with our private brand department about the information on our site regarding the springs and the lifters mentioned in the thread. We became "The World's Speed Shop" because of our customer service. We want to maintain that with the OP, this community, and our customer base worldwide!

Stay tuned. We'll be back with an update in the coming days

 

https://www.summitracing.com/parts/mll-s0007

It says out of stock because Joe sent that and the R&D team my way for installation. They're even going to double check the valve springs while I watch. Should be here Tuesday.

 

Lolololzzzzz

 

@4thGenCamaroZ28,

Thank you for the laugh! We were already out of the office at that time Friday, so seeing this on Monday morning almost made us spill our coffee

Kidding aside, we're glad we resolved this with you. We will be back soon with an update regarding the information on our site for springs and lifters.

 

Hey folks,

We wanted to let you know that we got @4thGenCamaroZ28 taken care of with a great deal on our TFS-2500286P duals and SUM-HTLSKIT2 lifter and tray kit. Now, let's address some of the questions and concerns raised by the community.

1. **Spring Rates for SUM-8707R1, SUM-8707-1, and SUM-8707-1DS**:
- We understand the confusion around the "pull strongly to 7000 rpm with as little as 150 lbs. of seat pressure" claim and the recommended spring with 130 lbs. of seat pressure.
- We mention the -1beehive kit as "pulling to 7K" and the -1DS duals as "pulling strongly through 7K".
- We've sold plenty of these cams with mostly positive feedback, especially with the beehive kits.
- The combo of our 8707R1 and SUM-174004 beehives can run out to 7000 rpm. As always, engine performance is all about the combo, ensuring everything works together optimally.
- We're working with our private brand department to provide clearer descriptions for our 8707R1 cam, and cam and spring kits.

2. **SUM-HTLSKIT Discontinuation and Lifter Specs**:
- The SUM-HTLSKIT, discontinued in 2020, was never made with LS7 or LS7-Spec lifters despite our previous statements included in the OP's screenshots.
- The lifters in that kit were of the Eaton design. The transition in 2020, complicated by the pandemic, led to the introduction of three lifter options:
- SUM-HT21416: Eaton design replacements used in the SUM-HTLSKIT1 lifter and tray kit.
- SUM-HT215-16: Made in the USA Delphi LS7’s used in the SUM-HTLSKIT2 lifter and tray kit.
- SUM-HT217-16: Made in USA Morel-7717's used in SUM-HTLSKIT3 lifter and tray kit.
- We're working on updating the discontinued SUM-HTLSKIT information to ensure it doesn't affect future purchasing decisions.

Our goal was to answer your questions and concerns. Our dedication to customer service is very important to us. A huge thanks to @4thGenCamaroZ28 for his patience as we worked through this.

We love being part of this community and helping out with recommendations. When questions or concerns arise, rest assured we're here to help. Carry on, folks

 

I'd like to thank Abs for asking the question. That question sent a notice to an email I rarely use and that's how it got my attention.

I would also like to mention that I don't really appreciate being treated like some dumbass in the threads I started about this in the past under different user names. Why different user names? Because this subject lead to me being banned at least two or three times.
And this started back in early 2020. Some threads I deleted out of frustration.

The LS1tech "experts" don't want to listen to me, when all I did was order parts based on the description.

The engine that does run good I built in 2020 and in one way or another I ended up with Brian Nutters personal phone number, this lead to information that probably is the reason why it runs so well. He's the lead engineer for the Summit Pro LS cams.

I never contacted him for the second build, the one that seems weak on the top end.

So for all the "experts" here, you really need to listen to what people say. As you can see in the post above I wasn't wrong based on what I thought I ordered.

Most of all thanks to Joe at Summit. I know there are different people behind Summits name here and I don't know who asked me if one of these two engines was boosted after I said they're built the same. Yea, the non boosted one seems slower for some odd reason, duh.

Bottom line is Thanks to Joe I have the means to try a few different things that may very well lead to this being resolved.