Clutch information and recomendations

Altered · 10-21-07, 10:07 PM

Ok a few weeks ago I got my first Corvette.

I am still learning about these cars as you may notice from some of my previous posts. What I am trying to find out is what transmission I have and try to pick out a new clutch before I disassemble it. I live in a small town and really dont want to have the car down for a week so I want to order the parts in advance. I guess I have several questions. This is for a 1976 Warner 4-Speedcar.

What spline do I have?
What diameter shaft do I have?
What diameter disc do I need?

I am installing a 427 big block in front of this tranny and want this clutch to hold what are the best clutches for this. I see different materials and brands but I have very little experience with performance clutches for standard transmissions. When I say clutch I am looking for the whole kit. Any links to the proper kits from Summit or Jegs etc are great.

I see KEVLAR, Organic, Iron/ Organic, materials what are the pros and cons of these?
What brands Centerforce, Zoom, Hays, RAM, and McLeod should I stay away from or is there a comon known favorite?

Thanks in advance

rocket22 · 10-22-07, 03:34 AM

Centerforce isn't bad, don't use the dual fricton line, Spec and Mcleod are also very good clutches. you most likely want a 10.5 clutch, and it should be a 26 spline input shaft. stay with a sprung clutch disc, meaning that the center of the clutch has springs to take the shock of engagement, and none sprung disc will chatter like mad, and be really tricky to drive around.

I had a Centerforce in my 69 with a 600 hp 427 and was a good clutch.

GTR1999 · 10-22-07, 09:40 AM

I've used a Hays in my 75-L82. It had the 11" clutch in it. The HP vettes used the 11" and the base eng used the 10.5 I believe.

If you go with a Centerforce you're going to have to check the geometry on the linkage as many setups have a problem with the pedal. You're going to need an adjustable ball stud most likely.

Altered · 10-22-07, 10:05 AM

Quote:

Originally Posted by rocket22

Centerforce isn't bad, don't use the dual fricton line, Spec and Mcleod are also very good clutches. you most likely want a 10.5 clutch, and it should be a 26 spline input shaft. stay with a sprung clutch disc, meaning that the center of the clutch has springs to take the shock of engagement, and none sprung disc will chatter like mad, and be really tricky to drive around.

I had a Centerforce in my 69 with a 600 hp 427 and was a good clutch.

So you recommend the Centerforce DFX ? Thats the one you ran? I was looking at that one and the RAM Powergrip HD. Never heard of Spec and didn't see any listed anywhere. The only McLeod Clutch on Summit for my application was the RST Street Twin Clutch and its pretty high. Around $400.00 is my budget I don't see any reason to spend $600.00 this is not a all out competition application. Ill look around for a better McLeod match I'm pretty sure there are some models closer to what I'm looking for. All the different models make it just that much more difficult to decide. Last night I finally figured out it should be a 10.5 and 26 spline so I appreciate the confirmation on that. I did notice that when I pull up my car on Summit it shows a lot of 11" ones. Can I use a 11" or would I have to change flywheel? Whats the benefit besides more surface area? Also read a lot of people were not happy with Zoom so I'm staying away from them.

Anyone else with experience on this. I just don't want to have to go back in there in 2 or 3 months because of a bad choice.
Thanks again for any input.

Altered · 10-22-07, 10:09 AM

Quote:

Originally Posted by GTR1999

I've used a Hays in my 75-L82. It had the 11" clutch in it. The HP vettes used the 11" and the base eng used the 10.5 I believe.

If you go with a Centerforce you're going to have to check the geometry on the linkage as many setups have a problem with the pedal. You're going to need an adjustable ball stud most likely.

Good info there thanks. I will keep that in mind.

JohnZ · 10-22-07, 03:08 PM

If you still have your original flywheel, it's drilled for an 11" clutch.

rocket22 · 10-22-07, 07:32 PM

Quote:

Originally Posted by Altered

So you recommend the Centerforce DFX ? Thats the one you ran? I was looking at that one and the RAM Powergrip HD. Never heard of Spec and didn't see any listed anywhere. The only McLeod Clutch on Summit for my application was the RST Street Twin Clutch and its pretty high. Around $400.00 is my budget I don't see any reason to spend $600.00 this is not a all out competition application. Ill look around for a better McLeod match I'm pretty sure there are some models closer to what I'm looking for. All the different models make it just that much more difficult to decide. Last night I finally figured out it should be a 10.5 and 26 spline so I appreciate the confirmation on that. I did notice that when I pull up my car on Summit it shows a lot of 11" ones. Can I use a 11" or would I have to change flywheel? Whats the benefit besides more surface area? Also read a lot of people were not happy with Zoom so I'm staying away from them.

Anyone else with experience on this. I just don't want to have to go back in there in 2 or 3 months because of a bad choice.
Thanks again for any input.

Yes, I had a DFX clutch, but one side note, My 69 had T-56 spd, but the clutch performance would be the same

I have Mcleod clutch in my 94 Z/28 whats a good clutch.

JohnZ · 10-23-07, 04:04 PM

I've used several Centerforce II's in project cars over the years with excellent results; the Dual-Friction is pretty extreme - hard on the flywheel surface.

Altered · 10-23-07, 08:25 PM

I emailed and asked each company for advise. This might help some other fellas to know what the reps from each company has responded.
My question was for the 1976 Corvette with at least a 500hp/500tq 427 in it. What would be the best clutch for 50% street and 50% strip or hard use time.
Centerforce

Quote:

Larry Clark:
Going to the 11" clutch, the DUAL FRICTION pressure plate and clutch
disc. part number DF148552 will go to 625 ft-lbs of Torque to the crank,
very street able and a soft pedal.
Our street and strip application. The LM Series 11" pressure plate and
clutch disc. part number LM148552 will take you up to 700ft-lbs of
Torque to the crank, this grabs quicker than the DUAL FRICTION. Our DFX
line is a 6 puk Metallic Button pressure plate and clutch disc. part
number 01148552 will go to 800 ft-lbs of Torque to the crank, you will
have to learn how to drive this on the street.

Reference Jegs lists LM148552 for $674.99 and DF148552 for $272.99.

Hays

Quote:

Technical Support Team
Use the Hays 11' STREET STRIP clutch application

Reference Jegs Hays# 40-221 - Street/Strip Discs 97.99 plus Hays 31-212 - Borg & Beck Pressure Plate $204.99 Total of $302.98

Mcleod I am still waiting to hear back

LUK

Quote:

Ron Timko / GV Account Manager
We appreciate your interest in LuK PRO GOLD PERFORMANCE Clutches! Regarding your inquiry, if your bell housing can accommodate an 11" Clutch with a 10 tooth spline, you may be able to upgrade to the LuK RepSet (04-049). I would, however, confirm this by calling the LuK Technical Hotline @ 800-274-5001 (8-6 EST) M-F, and one of our ASE certified technicians will be able to discuss in further detail.

Not really what I thought was a great response. 10 spline does not work for 1976 tranny. Instead of checking and responding with a correct response to me it was like he just threw this one out there so he could move on with his day.

RAM

Quote:

Doug RAM Tech
http://www.ramclutches.com/Specialty...eet_dual_2.htm
The link above will take you to our Street Dual Disc page, also check out
our clutch university at http://www.ramclutches.com/Clutch%20U/clutch_u.htm
It's full of great information and should help you make your decision.

The 90-2125 is the part number you'll need.

For anyone not familiar with clutch materials and pressure plate designs the "clutch university" link is AWSOME. It really explains some things that the average joe may have thought he knew in good detail, while still not getting to technical that you cant understand it. Reference Summit Racing part# 90-2125 $1,299.95

I will update as soon as I hear the other replies.

fine69 · 10-23-07, 10:38 PM

I have a LUK clutch. I'm happy with it.

Altered · 10-24-07, 12:39 AM

I havent checked with LUK. I dont know much about them just on a steep learning curve.

I will check with them. So far looks like Centerforce has a pretty good reputation. I have had more people recommend them than the rest combined.

Also I liked the way the reps from Centerforce discussed this with me. They were down to earth but explained how their clutches worked pretty good. Im still looking though.

Quote:

I have a LUK clutch. I'm happy with it.

I just emailed LUK I checked the Hi Perf line called Pro Gold and they didnt list one for my 76' Corvette.