8 Rib setup.. is it really worth it?
Thread Starter
Cruising
Joined: Jul 2025
Posts: 10
Likes: 0
From: Chicago
8 Rib setup.. is it really worth it?
Looking for honest opinions. I have gotten a lot of differing feedback so I wanted to bring the topic here.
2011 C6 GS M6. Forged 416 stroker, BoostLine Rods. Flex E85. Fresh rebuild. Monster stage 3 clutch. Stock trans, stock rear end. ECS trans brace, 355 rear tire.
ECS Novi 1500 - Build is finishing this week and I have to make the decision to either stick with the 6-rib or upgrade to the 8 (haven't sourced one yet, another part of discussion).
My main concern is whether or not I am tapped out on what the stock trans and rear end can handle for power, assuming I'd be able to achieve 900-950ish cto crank on E85. If someone were to tell me with certainty that the drivetrain can handle 1000'ish HP, and I could find an "affordable" 8-rib, I would likely lean that direction. If this will require several other upgrades, I'd likely settle with the 6-rib. Lastly, is there enough value in the 8-rib? Any real life numbers that can be shared with me on similar setups for HP rating?
If someone has a good link or contact for the 8-rib, please share that as well.
TIA.
2011 C6 GS M6. Forged 416 stroker, BoostLine Rods. Flex E85. Fresh rebuild. Monster stage 3 clutch. Stock trans, stock rear end. ECS trans brace, 355 rear tire.
ECS Novi 1500 - Build is finishing this week and I have to make the decision to either stick with the 6-rib or upgrade to the 8 (haven't sourced one yet, another part of discussion).
My main concern is whether or not I am tapped out on what the stock trans and rear end can handle for power, assuming I'd be able to achieve 900-950ish cto crank on E85. If someone were to tell me with certainty that the drivetrain can handle 1000'ish HP, and I could find an "affordable" 8-rib, I would likely lean that direction. If this will require several other upgrades, I'd likely settle with the 6-rib. Lastly, is there enough value in the 8-rib? Any real life numbers that can be shared with me on similar setups for HP rating?
If someone has a good link or contact for the 8-rib, please share that as well.
TIA.
Burning Brakes
Joined: Mar 2014
Posts: 1,238
Likes: 203
From: Lexington South Carolina
I am still running a 6 rib belt on my set up. I start getting belt slip when it hits around 12 psi. When I have a new really tight belt, I will hit 14 lbs. really depends on how hard you plan to beat on it.
Thread Starter
Cruising
Joined: Jul 2025
Posts: 10
Likes: 0
From: Chicago
Drifting
Joined: Aug 2017
Posts: 1,941
Likes: 364
From: Dayton, OH
A 10% OD will let you run a larger SC pulley with more wrap for the same amount of boost.
I am having an engine built. Planning to install a 10% OD 8 rib. Not that much cost differance and won't have to run the belt so tight.
I am having an engine built. Planning to install a 10% OD 8 rib. Not that much cost differance and won't have to run the belt so tight.
Thread Starter
Cruising
Joined: Jul 2025
Posts: 10
Likes: 0
From: Chicago
Premium Supporting Vendor
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From: Providing the most proven supercharger kits for your C5/6/7 609-752-0321
We upgrade to the direct drive at 700 rwhp, although we have had some customers run for years in the 800's, we do not recommend it. Direct drive units only come in two configurations, 8 rib is 10% over drive, and 10 rib is 15% over drive. So on a 1500 head unit the max RPM will be achieved with a 3.6" head unit pulley.
Racer
Joined: Oct 2018
Posts: 466
Likes: 158
From: ATX
Looking for honest opinions. I have gotten a lot of differing feedback so I wanted to bring the topic here.
2011 C6 GS M6. Forged 416 stroker, BoostLine Rods. Flex E85. Fresh rebuild. Monster stage 3 clutch. Stock trans, stock rear end. ECS trans brace, 355 rear tire.
ECS Novi 1500 - Build is finishing this week and I have to make the decision to either stick with the 6-rib or upgrade to the 8 (haven't sourced one yet, another part of discussion).
My main concern is whether or not I am tapped out on what the stock trans and rear end can handle for power, assuming I'd be able to achieve 900-950ish cto crank on E85. If someone were to tell me with certainty that the drivetrain can handle 1000'ish HP, and I could find an "affordable" 8-rib, I would likely lean that direction. If this will require several other upgrades, I'd likely settle with the 6-rib. Lastly, is there enough value in the 8-rib? Any real life numbers that can be shared with me on similar setups for HP rating?
If someone has a good link or contact for the 8-rib, please share that as well.
TIA.
2011 C6 GS M6. Forged 416 stroker, BoostLine Rods. Flex E85. Fresh rebuild. Monster stage 3 clutch. Stock trans, stock rear end. ECS trans brace, 355 rear tire.
ECS Novi 1500 - Build is finishing this week and I have to make the decision to either stick with the 6-rib or upgrade to the 8 (haven't sourced one yet, another part of discussion).
My main concern is whether or not I am tapped out on what the stock trans and rear end can handle for power, assuming I'd be able to achieve 900-950ish cto crank on E85. If someone were to tell me with certainty that the drivetrain can handle 1000'ish HP, and I could find an "affordable" 8-rib, I would likely lean that direction. If this will require several other upgrades, I'd likely settle with the 6-rib. Lastly, is there enough value in the 8-rib? Any real life numbers that can be shared with me on similar setups for HP rating?
If someone has a good link or contact for the 8-rib, please share that as well.
TIA.
Drifting
Joined: Aug 2017
Posts: 1,941
Likes: 364
From: Dayton, OH
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Le Mans Master
Joined: Dec 2007
Posts: 8,375
Likes: 97
From: Somewhere in the Mid 9's TX
ECS 1500, LS2 402, Greg Good ported LS3 heads, intake, my sleeper cam. 93+meth 14 years ago. 850rwhp/800rwtq. Had a 100 shot on top of it but not used here. 6 rib, 3.125 pulley, Dallas Performance direct drive. Beat the crap out of this car daily, 1/4 mile, 1/2 mile etc.
Racer
Joined: Oct 2018
Posts: 466
Likes: 158
From: ATX
This!!!!
Likely you will change the TI for something larger on a 427 down the road and will not want to deal with belt slip. Everyone wants to save a buck and get everything from the small belt. It will leave you on the side of the road. Vortech/Paxton run awful setup ratios requiring you to run baby pulleys. So you want a wide belt to get everything you can from the setup. You will toss the 6 rib on high end pulls and sometimes on a shift because the belt is so long. Its just a common thing. With 8 rib you can get a lot but if there is ever a goal of 1000whp you will have to stretch the belt to the limit so it doesn't slip. It will end up snapping from being too tight or missing a shift. If your lucky it only takes out the blower belt not the accessory belts. 10 rib it... One and done!!
Likely you will change the TI for something larger on a 427 down the road and will not want to deal with belt slip. Everyone wants to save a buck and get everything from the small belt. It will leave you on the side of the road. Vortech/Paxton run awful setup ratios requiring you to run baby pulleys. So you want a wide belt to get everything you can from the setup. You will toss the 6 rib on high end pulls and sometimes on a shift because the belt is so long. Its just a common thing. With 8 rib you can get a lot but if there is ever a goal of 1000whp you will have to stretch the belt to the limit so it doesn't slip. It will end up snapping from being too tight or missing a shift. If your lucky it only takes out the blower belt not the accessory belts. 10 rib it... One and done!!
Racer
Joined: Oct 2018
Posts: 466
Likes: 158
From: ATX
Drifting
Joined: Aug 2017
Posts: 1,941
Likes: 364
From: Dayton, OH
Called ATI this morning. PN 917309
This is for a 1997 to 2013 LS1, 2, 3, 6 in a Y body, G8, or SS
8.275" diameter. Use 8.175" to calculate CSC impeller speed. 3.8" on the CSC will give you 54,213 RPM impeller at 7,000 RPM.
That is a little fast for a typical V-3. Mine has upgraded bearings.
We are going to pin it.
Last edited by SteveJewels; Dec 30, 2025 at 07:13 AM.
Racer
Joined: Aug 2006
Posts: 401
Likes: 85
From: Terre Haute Indiana
I'll chime in even though I'm in a c5. I recently built a 403 LS2 and running a Novi 2000 unit. When I first got the build complete, I was running 6 rib. I snapped 3 belts on high pull shifts. The last one took out my oil drain line. Talked with ECS, builder, and tuner. They all recommended at least going to an 8. ECS said direct drive, but cost limited me due to the build.
I already had the 8 rib ATI on knowing I would go to the 8 rib setup later. The rest of the 8 rib pulleys were easy to find and were relatively affordable.
Since the switch from 6 to 8, I haven't had any belts snap (yet) but I haven't really driven it a lot since. But so far it's holding. I'm right about 11 psi and my numbers are 780/660.
I would highly suggest going with the 8. It'll save headache with belts bc I would say you're going to be snapping them if you're hard on it.
I already had the 8 rib ATI on knowing I would go to the 8 rib setup later. The rest of the 8 rib pulleys were easy to find and were relatively affordable.
Since the switch from 6 to 8, I haven't had any belts snap (yet) but I haven't really driven it a lot since. But so far it's holding. I'm right about 11 psi and my numbers are 780/660.
I would highly suggest going with the 8. It'll save headache with belts bc I would say you're going to be snapping them if you're hard on it.
Thread Starter
Cruising
Joined: Jul 2025
Posts: 10
Likes: 0
From: Chicago
Thank you for all the replies, made the decision and paid for the 8-rib this AM. Ton of valid points on the upgrade, especially the reliability standpoint. Buy once cry once, right? (I've been crying for months over this build though LOL)
Thanks fellas! Enjoy your New Years.
Thanks fellas! Enjoy your New Years.
Racer
Joined: Mar 2013
Posts: 468
Likes: 26
From: Ok/Tex
Thank you for all the replies, made the decision and paid for the 8-rib this AM. Ton of valid points on the upgrade, especially the reliability standpoint. Buy once cry once, right? (I've been crying for months over this build though LOL)
Thanks fellas! Enjoy your New Years.
Thanks fellas! Enjoy your New Years.
I’m not trying to be a smartass, but I initially went with an 8 rib setup and ended up switching to a 10 rib. The 8 rib left me stranded on the side of the road three times, which was incredibly frustrating. Sure, I’m over 1,000 rwhp, but reaching that isn’t as hard as you might think.
I just re-read you first post.... your 8 rib is gonna be on borrowed time. I suggest learning how to change the belt on the side of the road.
