Check out the NEWEST Summit Pro LS Cams
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That's some great results with that. I just wonder how elevation ties into cam selection? Im sure it will matter less when the turbo is installed. I know the 6.0 can get away with bigger cams vs the two smaller displacements also
I'll be using the nnbs intake which is the same as the trail blazer. And cheap eBay shorty headers untill the swap. Thank you for adding
I'll be using the nnbs intake which is the same as the trail blazer. And cheap eBay shorty headers untill the swap. Thank you for adding
The cams Summit posted above sound good, and very similar to what I'm running. You can't go wrong with them. I just got another summit box dropped off today. I think I could do a vinyl wrap just made out of summit stickers, I have so many....
Teching In
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Thanks for checking in on the thread for a cam recommendation. The community has provided some good advice for you.
You've provided a good amount of combo info along with your goals. Altitude does change up things when we're recommending a cam. The air is not going to be good up there. To help counter the poor air we like to try and boost compression and or cylinder pressure. Obviously, you'll need the Octane to support it.
A cam we're thinking of is our Pro LS stage 2 high-lift truck cam. That's part number SUM-8720R1 with specs of .600/.600, 218/227, 112+2 with -1* of overlap. This will have a fairly mild idle with its -1* IVO. You can get a noticeable lope with a low idle speed. The combined 39* IVC and 46* EVO will help boost dynamic compression and cylinder pressure. This will help keep the engine from feeling lazy in the poor air. By keeping the EVC at 0* ATDC we limit overlap and help prevent exhaust reversion from getting back into the intake. This is a plus for throwing boost at it.
The 8720R1 will be plenty happy to spin up to 6,500+ with a good .600 lift beehive. We carry the PAC 1218 beehive through Trickflow as TFS-16918-16. If you're one for added insurance go with the TFS-2500286 duals. You could use the stock converter with this cam. However, a 2,500+ converter would be a plus.
If you want something with more bark to it there's another option we could see working here. Our stage 3 truck cam is what we have in mind. That's part number SUM-8713R1 with specs of .550/.550, 222/232, 112+5 with 3* of overlap. This will shift the powerband up a bit by opening the exhaust valve fairly early at 53* BBDC vs. the 46* of the stage 2. It'll keep cylinder pressure up by drawing the IVC back another degree to 38*. You'll also get a nice steady lope at idle if that's something you're after with the 4* IVO.
The stage 3 would be happy with budget-friendly LS6 springs. For an upgrade, you could go with the previously mentioned TFS-16918-16 beehives. You'll certainly need a higher stall converter here. We recommend a minimum of a 2,500 converter.
Something else you could do to boost compression is put in a thinner head gasket like a .040" Cometic. That would boost static compression to right around 10.5:1. This is a respectable target for use with 91 Octane. By reducing the head gasket thickness you're also decreasing the quench distance. This will help reduce the chance of knock which is a plus for when you're in poor air.
If you have any further questions don't hesitate to ask us here or shoot us a PM!
You've provided a good amount of combo info along with your goals. Altitude does change up things when we're recommending a cam. The air is not going to be good up there. To help counter the poor air we like to try and boost compression and or cylinder pressure. Obviously, you'll need the Octane to support it.
A cam we're thinking of is our Pro LS stage 2 high-lift truck cam. That's part number SUM-8720R1 with specs of .600/.600, 218/227, 112+2 with -1* of overlap. This will have a fairly mild idle with its -1* IVO. You can get a noticeable lope with a low idle speed. The combined 39* IVC and 46* EVO will help boost dynamic compression and cylinder pressure. This will help keep the engine from feeling lazy in the poor air. By keeping the EVC at 0* ATDC we limit overlap and help prevent exhaust reversion from getting back into the intake. This is a plus for throwing boost at it.
The 8720R1 will be plenty happy to spin up to 6,500+ with a good .600 lift beehive. We carry the PAC 1218 beehive through Trickflow as TFS-16918-16. If you're one for added insurance go with the TFS-2500286 duals. You could use the stock converter with this cam. However, a 2,500+ converter would be a plus.
If you want something with more bark to it there's another option we could see working here. Our stage 3 truck cam is what we have in mind. That's part number SUM-8713R1 with specs of .550/.550, 222/232, 112+5 with 3* of overlap. This will shift the powerband up a bit by opening the exhaust valve fairly early at 53* BBDC vs. the 46* of the stage 2. It'll keep cylinder pressure up by drawing the IVC back another degree to 38*. You'll also get a nice steady lope at idle if that's something you're after with the 4* IVO.
The stage 3 would be happy with budget-friendly LS6 springs. For an upgrade, you could go with the previously mentioned TFS-16918-16 beehives. You'll certainly need a higher stall converter here. We recommend a minimum of a 2,500 converter.
Something else you could do to boost compression is put in a thinner head gasket like a .040" Cometic. That would boost static compression to right around 10.5:1. This is a respectable target for use with 91 Octane. By reducing the head gasket thickness you're also decreasing the quench distance. This will help reduce the chance of knock which is a plus for when you're in poor air.
If you have any further questions don't hesitate to ask us here or shoot us a PM!
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I think that settles it! Ive been looking at the 8720r1 so with what you said swayed my decision that way. Sadly I already have the head gaskets, but thats something I never even thought about. So I learned a little about quench distance and its relation to knock. Thank you for all you do and have done in this thread!
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That's awesome Project GatTagO! Thank you for your patronage. That's a great trifecta of parts right there. Be sure to update us on your 1970 GTO Version 3.0 build thread once you have it up and running!
Quick question for Joe or anyone else.
I've got a customer with a Stage 4 NA cam, 8711. It seems to not be pulling much vacuum at idle. It is idling around 70kPa.
I am trying to determine if that's normal for this cam or if I need to be chasing down other issues. Given the cam specs, I expect something around 60kPa...
Andrew
I've got a customer with a Stage 4 NA cam, 8711. It seems to not be pulling much vacuum at idle. It is idling around 70kPa.
I am trying to determine if that's normal for this cam or if I need to be chasing down other issues. Given the cam specs, I expect something around 60kPa...
Andrew
Thread Starter
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Joined: Jan 2008
Posts: 2,233
Likes: 1,521
From: Ohio, Georgia, Nevada, Texas
Quick question for Joe or anyone else.
I've got a customer with a Stage 4 NA cam, 8711. It seems to not be pulling much vacuum at idle. It is idling around 70kPa.
I am trying to determine if that's normal for this cam or if I need to be chasing down other issues. Given the cam specs, I expect something around 60kPa...
Andrew
I've got a customer with a Stage 4 NA cam, 8711. It seems to not be pulling much vacuum at idle. It is idling around 70kPa.
I am trying to determine if that's normal for this cam or if I need to be chasing down other issues. Given the cam specs, I expect something around 60kPa...
Andrew
Thats the 234 degree extra p to v version and intake opening is 7 Btdc. It makes killer power but a lot of folks really like the 230 degree sum-8710r1 with intake opening at 5 btdc. It picks up 15 ft lbs at 3500 and is down about 7 at peak on a typical Ls3 but 8711r1 always makes folks happy with the power.
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From: Ohio, Georgia, Nevada, Texas
In our testing on a fairly stock-ish LS3 and depending on the rpm, 65-70 can be expected. 900-925 will smooth it ,but people buying this cam are generally looking for a lot of character and top end power.
Thanks!
Andrew
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From: Lawrenceburg Ky
Hi Summitracing , with the 468 up and running in the race truck, I'm now concentrating on my 95 S10 street truck and need a good cam recommendation from you. It's got a fresh stock bore x stroke LM7 5.3, PRC 220 heads, Fast 102 intake, NW 102mm throttlebody, 1 7/8 long tube headers, 350 turbo, 3800 stall, 4.10 gears. The current cam is a BTR stage 2, I've read some of the articles online using your stage 4 cam in a 5.3 and making big power without giving up anything down low. I do drive this on the street occasionally. What would you recommend?
Last edited by BigDaddy97; Jul 24, 2021 at 07:10 PM.
Thread Starter
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From: Ohio, Georgia, Nevada, Texas
Hi Summitracing , with the 468 up and running in the race truck, I'm now concentrating on my 95 S10 street truck and need a good cam recommendation from you. It's got a fresh stock bore x stroke LM7 5.3, PRC 220 heads, Fast 102 intake, NW 102mm throttlebody, 1 7/8 long tube headers, 350 turbo, 3800 stall, 4.10 gears. The current cam is a BTR stage 2, I've read some of the articles online using your stage 4 cam in a 5.3 and making big power without giving up anything down low. I do drive this on the street occasionally. What would you recommend?
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From: Lawrenceburg Ky
We know you like to party and there are a couple good choices for something that spends a bit of time on the street. The Sum-8710r1 is the 230 degree cam and intake closing is at 45 degree abdc. This would be a great match for the three speed and pretty punchy. The one that would probably behave a little more like what you expect it to is indeed the stage 4 Sum-8711R1 234 cam with its 47 degree intake closing. Overlap goes up from 10 to 14 with that and your exhaust system will make that cam happy. You should have plenty of p to v and we’d whack the heads .030 to get some compression into it with either cam. Keep us posted!
SummitRacing, same LM7, but in a full weight m6 4th gen f-car. 1 7/8" kooks into borla catback, stock LS6 manifold w/stock f-car throttlebody (75/78 mm? who knows, i dont have one to measure), 3.42 gear, 93 octane, street/strip. looking for cam recommendations and smaller chambered heads to raise compression. willing to flycut pistons if needed.
Last edited by slowpoke96z28; Aug 30, 2021 at 06:16 PM.
Staging Lane
Joined: May 2015
Posts: 53
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From: Kentucky
Hello Summit! Looking for recommendations on my setup. Car is a 84 Corvette being setup for Auto-x. Car will weigh in under 3000#’s, use a manual valve body 700r4 (stall will match the cam selection), and use stock style suspension.
Engine is LC9 aluminum block 5.3 with factory 3cc valve relief pistons, 706 heads (shooting for 10.5 compression via correct head gasket thickness), shorty headers and ls6 intake. Like to cap the rpm’s to 6800 to 7200 max. Looking at the 8707 and 8720. Thanks!
Engine is LC9 aluminum block 5.3 with factory 3cc valve relief pistons, 706 heads (shooting for 10.5 compression via correct head gasket thickness), shorty headers and ls6 intake. Like to cap the rpm’s to 6800 to 7200 max. Looking at the 8707 and 8720. Thanks!
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Hello Summit! Looking for recommendations on my setup. Car is a 84 Corvette being setup for Auto-x. Car will weigh in under 3000#’s, use a manual valve body 700r4 (stall will match the cam selection), and use stock style suspension.
Engine is LC9 aluminum block 5.3 with factory 3cc valve relief pistons, 706 heads (shooting for 10.5 compression via correct head gasket thickness), shorty headers and ls6 intake. Like to cap the rpm’s to 6800 to 7200 max. Looking at the 8707 and 8720. Thanks!
Engine is LC9 aluminum block 5.3 with factory 3cc valve relief pistons, 706 heads (shooting for 10.5 compression via correct head gasket thickness), shorty headers and ls6 intake. Like to cap the rpm’s to 6800 to 7200 max. Looking at the 8707 and 8720. Thanks!
Staging Lane
Joined: May 2015
Posts: 53
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From: Kentucky
Current gearing hasnt been fully decided. I know it will be in the 3.55 to 4.10 range. As for compression, I was trying to keep it budget friendly without major work. The 706's with a .040 gasket should be in that 10.5:1 range. I will be NA on pump gas if that makes a difference on your higher compression recommendation. Tia!
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The higher compression ratio would run fine on premium pump gas. But if milling your heads is not in the budget, the 8720 would be the better choice in the 5.3L. It should pull up to 7k with a wide useable power band for less down/up shifting (depending on the track layout this can save a lot of time); and more midrange to get you off the slow corners quicker (especially with the "low" compression and shorty headers).
Last edited by 68Formula; Aug 30, 2021 at 08:33 PM.