C3 Differential - Clutch Pack Recommendations
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Joined: Jan 2014
Posts: 74
Likes: 17
From: Hermitage TN
C3 Differential - Clutch Pack Recommendations
Looking for recommendations regarding the type of clutch pack for a C3 differential. Solid steel vs HD Carbon Fiber.
I have (for the most part, some mods to cam and pistons) a stock 79 L82 with 4-speed. Previously had the original 3.70 gear but replaced it with a 3.08 in an attempt to reduce RPM on HWY trips and to improve gas mileage. The 3.08 only dropped RPM from 3500 to 3000 at 70 MPH and gas mileage still below 12 MPG. SO... I'm putting the 3.70 back in after 10 years with the 3.08. Current mileage is 135K.
I've read the clutch pack option should be solid steel but I've seen the option for HD Carbon Fiber from Duntov Motors. Looking for recommendations and why.
Use is weekend car on nice days.
Thanks in advance for your time and feedback.
I have (for the most part, some mods to cam and pistons) a stock 79 L82 with 4-speed. Previously had the original 3.70 gear but replaced it with a 3.08 in an attempt to reduce RPM on HWY trips and to improve gas mileage. The 3.08 only dropped RPM from 3500 to 3000 at 70 MPH and gas mileage still below 12 MPG. SO... I'm putting the 3.70 back in after 10 years with the 3.08. Current mileage is 135K.
I've read the clutch pack option should be solid steel but I've seen the option for HD Carbon Fiber from Duntov Motors. Looking for recommendations and why.
Use is weekend car on nice days.
Thanks in advance for your time and feedback.
Last edited by Rods 79; Feb 9, 2017 at 03:41 PM. Reason: Moving this request to correct Forum
Melting Slicks
Joined: Mar 2008
Posts: 2,666
Likes: 289
From: Spring Park MN
Looking for recommendations regarding the type of clutch pack for a C3 differential. Solid steel vs HD Carbon Fiber.
I have (for the most part, some mods to cam and pistons) a stock 79 L82 with 4-speed. Previously had the original 3.70 gear but replaced it with a 3.08 in an attempt to reduce RPM on HWY trips and to improve gas mileage. The 3.08 only dropped RPM from 3500 to 3000 at 70 MPH and gas mileage still below 12 MPG. SO... I'm putting the 3.70 back in after 10 years with the 3.08. Current mileage is 135K.
I've read the clutch pack option should be solid steel but I've seen the option for HD Carbon Fiber from Duntov Motors. Looking for recommendations and why.
Use is weekend car on nice days.
Thanks in advance for your time and feedback.
I have (for the most part, some mods to cam and pistons) a stock 79 L82 with 4-speed. Previously had the original 3.70 gear but replaced it with a 3.08 in an attempt to reduce RPM on HWY trips and to improve gas mileage. The 3.08 only dropped RPM from 3500 to 3000 at 70 MPH and gas mileage still below 12 MPG. SO... I'm putting the 3.70 back in after 10 years with the 3.08. Current mileage is 135K.
I've read the clutch pack option should be solid steel but I've seen the option for HD Carbon Fiber from Duntov Motors. Looking for recommendations and why.
Use is weekend car on nice days.
Thanks in advance for your time and feedback.
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Joined: Oct 2008
Posts: 59
Likes: 1
From: Milton Florida
Thanks for bringing this up. I've been thinking about rebuilding my diff and have had the same question. I have a 3:36 diff and recently installed a Tremec 5 spd from Silver Sport transmissions. The install went well and it dropped my rpms by close to 1000! 
Just a thought!
Just a thought!
