DualQuadDave

iTrader: (6)

Question, how well does your 8708r1 or 8710r1 work with 1.8 rockers? Stable? I would be running that combo w/ a Comp 1.8 roller rocker and Pac1207x springs.

Summitracing

@bh10,

Thanks for getting back to us with more info. We do like the 8720R1 for this combo and goals. As @68Formula said the SUM-8728R1 "Big Truck Torkinator" would be a good option if you're focused on low and mid-range torque with good efficiency. Specs on it are .600/.585, 212/218, 110+3 with -5* of overlap. The 8728R1 would work well N/A or with boost.

We think you'd be happy with either the 8720R1 or the 8728R1. Our SUM-174004 .600" lift beehive spring pack will pair well with either of these cams.

To make Pro LS cam swaps easier we offer a variety of cam combos.
- For 8720R1 combos check here
- For 8728R1 combos check here

You'll want to upgrade pushrods as well. We typically see a 7.400" or 7.425" pushrod work for either of these cams. However, things can vary so we always recommend checking pushrod length before purchasing pushrods. The Trickflow TFS-9501 pushrod length checker will help with finding the correct pushrod length for your combo. For pushrods, we recommend a minimum of a 5/16" Chromoly pushrod with a .080" wall. You can typically find a set of 16 for around $100.

Let us know if we can be of any further assistance. We'll be happy to help!

Summitracing

@DualQuadDave,

Thanks for checking in with us on the SUM-8708R1 or SUM-8710R1 working with your 1.8 rockers and PAC-1207X RPM series springs. Those are great springs that will help keep the valvetrain happy with the 1.8 rockers. Either of these cams would be stable out past 7,000 rpm. Our Pro LS cams are finish machined on a Landis 3L Cylindrical CNC Grinder using a CBN (diamond) wheel. This gives us very smooth and consistent lobes. For an in-depth look into the manufacturing process of Pro LS cams see this article from our onallcylinders Blog.

Something to keep in mind about the 1.8 roller rockers. They will make more power and with a higher peak. However, due to the increased mass power will fall off sooner past peak compared to a factory rocker.

Make sure to put a good pushrod in there to ensure valvetrain stability. This would be a combo where we would want more than a .080" wall 5/16" pushrod. We would recommend our HDR Thickwall Chromoly pushrods. The 11/32" pushrods with a .120" thick wall have 25% less stress and 28% less deflection than a typical 5/16" x .080" wall Chromoly pushrod. These will fit factory or aftermarket heads.

This was a great question Dave. We're happy to see this thread created in October 2018 continuing to provide value for the community. Keep them coming folks, we're here to help!

DualQuadDave

iTrader: (6)

Thank you for the info👍

I plan to run a 3/8 ..080 wall pushrod in this combo. Would be going with a set of PRC 260 cnv heads on a 6.0. As long as I can keep it stable to about 74/7500 ish, that is plenty. I expect peak around 7000 or so. I would like to run even more spring, but trying to balance it out w/ a LS7 lifter. May take the plunge and get some 2110r's, just so expensive for what it is. Thanks again!

bh10

@Summitracing Thanks! One last question, looking at the kits looks like there's 3 (really 4 w/ TI retainers on the dual), but what spring would you recommend? The Pac TFS-16918, SUM-174005 or SME-174003? One better for my application or not? On past LS builds Ive always run BTR Dual Springs, but looking at prices the Pac springs are more expensive than y'alls duals, w/ y'alls single beehive being the cheapest

Summitracing

The SUM-174004 .600" lift beehives pair well with either the 8728R1 or 8720R1. As an upgrade we'd go with the SUM-174005 .630" lift beehives. If you're one for added insurance there are the TFS-2500286P .660" lift duals. If you need help putting a combo together we're only a PM away!

Project GatTagO

iTrader: (7)

I want to bump this up for anyone that is interested. I have a customer who recently swapped out the mystery cam in his 5.3L swapped Datsun 240Z for a Summit Ghost cam.

The old cam had similar duration numbers bust I suspect it had pretty tight LSA. It idled around 60kPa and didn't have very good street manners, even after fiddling with the tune. It also didn't like to idle at anything less than 900RPM, which in itself is not a big deal, but not what he wanted.

With the Ghost cam it now idles at 750RPM, with a mellow exhaust note and a tiny bit of chop. It makes a lot more vacuum (48-50kPa at idle now, with less timing at idle) and the street driving manners are greatly improved. It also has better throttle response and I also know from experience that it will run great and make excellent power.

Andrew

grubinski

Update:

I went from the non-sprung hub 25# clutch and flywheel setup I had (RPS BC Carbon II) to a Mantic twin disc organic with a total weight of 34# for clutch and flywheel.

The car drives perfectly smoothly now. Thanks for the good advice!

Escalado

hey there, I am looking for a drop in camshaft for a 2000 Silverado 5.3 lm7 w/
25 lb injectors
coils, plugs, wires,
2nd battery, 145amp alternator
efans
bigger radiator
Cat back exhaust
12212156 O/S with 2002 settings
3:73 gears
vette servo and sonnax 4th

I don’t want to go wild with it, as it’s my daily driver, I don’t tow or haul regularity, but every once in a while I do. Definitely want more power, more responsive power through low/mid would be nice. Which of the three stage 1 truck cams would be best at producing across the board?

Summitracing

Escalado,

Thanks for checking in on the thread for a cam recommendation.

If you're looking for a drop-in no springs required cam we'd go with the SUM-8718R1 tow/rv cam. Specs on it are .500/.500, 205/217, 112+2 with -12* of overlap. It produces outstanding torque off idle and maintains efficiency. Idle speed can be tuned for a smooth idle or slight lope. No springs are required but budget-friendly LS6-Style springs are a good idea to extend the rpm range. Tuning not required but highly recommended for this cam.

If you're ok with changing out springs and pushrods we'd go with the SUM-8719R1 stage 1 high-lift cam. Specs on it are .550/.550, 209/217, 112+1 with -11* of overlap. It produces good torque off-idle with a strong mid-range and top-end. The increased lift will improve hp/tq across the entire range. Idle speed can be tuned for a smooth idle or noticeable lope. With the same budget-friendly LS6-Style springs above the 8719R1 will be happy out to 6,500+. We recommend upgrading pushrods with the 8719R1's .550" lift. We typically see a 7.400" pushrod used. However, things vary so you should always measure for pushrod length before purchasing pushrods. Tuning would be required to use this cam.

It's where you want the power and what you want to change to work with the cam. The intake valve closing is what sets the powerband of a cam. The earlier we close the intake valve the lower the powerband starts and ends. The 8718R1 has a 33* IVC @.050" lift. The 8719R1 has a 36* IVC @.050" lift. So the 8719R1 will move the power a bit to the right from the 8718R1.

We think you'd be happy with either of these two cams. Either will put a smile on your face and work well with your combo!

Escalado

Hey thank you for the reply. Right now I have stock converter, I seem to be feeling power start around 2000 rpm atm. I’d like to increase power/hp, but not move that power band Too much further out of that. What range will the 8719 start being felt? Do you have any Dyno comparisons for a 8718-8719? I don’t mind doing springs at all, or pushrods if they aren’t too hard to do. I don’t mind going to a stage 2 cam if needed, but I want most of the power band to be low/mid

68Formula

If you want to keep that powerband, you're best bet is probably the SUM-8727R1. You'll still need to upgrade the springs and pushrods.

Escalado

Okay, so out of these three you’d recommend the 8727? How does it change the drive feel if moving the power band up? What about the 8718 torque cam, is that similar to the Torkinator? I very rarely tow, I’m just looking for a punchier feeling drive, with aggressive sounding idle

Summitracing

Quote:

Originally Posted by Escalado

Hey thank you for the reply. Right now I have stock converter, I seem to be feeling power start around 2000 rpm atm. I’d like to increase power/hp, but not move that power band Too much further out of that. What range will the 8719 start being felt? Do you have any Dyno comparisons for a 8718-8719? I don’t mind doing springs at all, or pushrods if they aren’t too hard to do. I don’t mind going to a stage 2 cam if needed, but I want most of the power band to be low/mid

Quote:

Originally Posted by 68Formula

If you want to keep that powerband, you're best bet is probably the SUM-8727R1. You'll still need to upgrade the springs and pushrods.

Quote:

Originally Posted by Escalado

Okay, so out of these three you’d recommend the 8727? How does it change the drive feel if moving the power band up? What about the 8718 torque cam, is that similar to the Torkinator? I very rarely tow, I’m just looking for a punchier feeling drive, with aggressive sounding idle

Sorry for the late reply. We 100% agree with @68Formula that the SUM-8727R1 would be the way to go focusing on low-end hp/tq. With its -9* intake valve opening you're not going to have a choppy idle. If you wanted a cam that had an idle to it you'll have to compromise a bit on where you want the power. If you don't mind losing some off-idle torque to get your "aggressive sounding idle" take a look at the SUM-8728R1. It will make up for it and then some come 2,000 rpm on up. The Intake Valve Closing is basically what sets the powerband of a cam. The earlier we close the intake valve after bottom dead center the earlier the powerband starts and ends. The 8727R1 has a 29* IVC @.050" lift. Whereas the 8728R1 has a 33* IVC @.050" lift. The 8728R1 will work just fine with your 3:73 gears and stock converter.


With the 8728R1 you will need to move up to .600" lift beehives. You'll also want upgraded pushrods. With the 8728R1, we typically see a 7.400" or 7.425" pushrod used. Things can vary so we always recommend measuring for pushrod length before purchasing pushrods. If you don't already have a pushrod length checker we offer the Trickflow TFS-9501. For pushrods, we recommend a minimum of a 5/16" Chromoly pushrod with a .080" wall. You can typically find a set of 16 for around $100. From there you can get into a thicker wall or larger diameter pushrod. For excellent stability and strength check out our 11/32" HDR pushrods with a .120" wall. These have 25% less stress and 28% less deflection than a typical 5/16" x .080" wall Chromoly pushrod.

Black0ut

What are the lobes like on the 8710R1 and 8711R1? In terms of spring life and valvetrain stability?

Utinator

Has anyone used the "Big Gun" cams yet? I have been thinking about building a 415-ish stroker, and I was considering the Big Gun-2 cam. The description doesn't really say what application these cams were meant for, but the specs look like stroker territory.

Pro LS Big Gun 1
Part Number: SUM-8729R1
240/247, 115.5 + 5.5, .625/.605

Pro LS Big Gun 2
Part Number: SUM-8730R1
242/251, 116 + 6, .625/.605

Pro LS Big Gun 3
Part Number: SUM-8731R1
247/255, 117 + 7, .625/.605

Summitracing

We replied to your thread about a cam recommendation but figured we'd respond here as well about the manufacturing of our cams.

They are smooth! To start with our cams are 100% made in the USA They are made of a 5150 core with smooth consistent lobes. They are finish machined on a Landis 3L Cylindrical CNC Grinder using a CBN (diamond) wheel. To finish it off they are quality tested on precision Adcole equipment to ensure they meet our stringent quality standards!

For full details with a ton of info and pictures check out this article on the manufacturing process of our Pro LS cams!

Just as important as the cam itself is its supporting valvetrain. Make sure to go with a spring pack and pushrods that support the use and rpm you're after.

Summitracing

Certainly, with the size and valve events of the Big Gun cams, they could be good candidates for a stroker. With more info on your combo and goals, we could make a recommendation.

TrendSetter

@Summitracing i have a ls3 with good dual springs going in a awd silverado. i softened the chambers on the heads and will try to get compression right around 9.8-10.0. probably 4600lb weight, 4.10 gears, converter is in the 3600 range but i want to send it out for a reflash anyway. daily driver but i want to push it pretty hard, going to use twin t4 cast 7875s since i have a pair on the shelf.
since its in a truck im hesitant to use your smallest twin turbo cam, and am leaning toward the 8707 stage 2. thoughts?

68Formula

If you're concerned about low speed driveabilty, SUM-8706R1 would be a better choice rather than the 8707. But with your setup it should still run pretty good with the slightly larger SUM-8722R1.