Clutch Selection- Really Need Your Advice!

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4mm

Well-known member
Joined
Aug 26, 2012
Messages
447
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Location
S. TX
My Car
1971 Mustang 351C 4V Fastback
Need your help again guys...

I have a Boss 351 modified with headers and intake. I purchased a blow-proof flywheel and new dampener for insurance (plus they are lightened by around 20%) so I can safely drive the car however I want without worries.

I have narrowed down the clutch and pressure plate selection to the four choices linked below.

Which one would you recommend and why? Anyone with personal experience with either one? Thanks in advance.

I am leaning towards the Mcleod in the last link (not because of price but due to its stock application).

1. Zoom Kevlar

http://www.summitracing.com/parts/zzz-hp7350-1/overview/year/1971/make/ford/model/mustang

2. Ram HDX

http://www.summitracing.com/parts/ram-88769hdx/overview/year/1971/make/ford/model/mustang

3. Standard Ram http://www.summitracing.com/parts/ram-92769/overview/year/1971/make/ford/model/mustang

4. Mcleod StreetPro

http://www.summitracing.com/parts/mcl-75111/overview/year/1971/make/ford/model/mustang

 
the zoom is junk.

the mcleod street disc is not good enough to take much abuse . if you dump the clutch and speed shift etc, i would use a dual friction mcleod or centerforce disc.

don't buy a pressure plate unless you know what the pressure is so you can have an idea on how hard it will be to depress the clutch pedal . if you only subject it to moderate abuse and don't want a heavy clutch pedal, i would use an 1850 lb pressure plate.

mcleod will build a late to your spec if you want.

.

 
I can only add to this from my own experience, I'm not an expert on clutches..........or anything else for that matter.

On my 71 351C 4V M code, I chose a Centerforce II. It was a bit heavy at first, but after it was broken in, the pedal pressure was acceptable (the wife hates it and that's a good thing!!) I thought about upping it to the Dual Friction, but as I don't have high HP, I could not justify the extra expense. Currently, my engine is out being rebuilt. I took this opportunity to take out my steering column and pedal support bracket ( taking out the column makes it easy to get the bracket out). I had Mustang Steve's clutch pedal bearing kit added and I also modified all the linkage joints with bronze bushings. PM me if you want more details, but this subject was covered in earlier threads. As mentioned, my engine is out so all these upgrades are yet to be tested, but I'm very optimistic that my pedal will be a lot easier to operate.

If you go to the Centerforce website, you can find a ton of info. Also I found the 'Centerforce University'. There are video's that explain their clutches. Try www.youtube.com/watch?tv=Xbqa9L4QCUM or Google centerforce and you'll find it there.

Hope this helps some.

Geoff.

 
Thanks Barnett and Geoff. I should have first mentioned I have to stick to a long style clutch due to the Yella Terra flywheel.

 
Thanks Barnett and Geoff. I should have first mentioned I have to stick to a long style clutch due to the Yella Terra flywheel.
Ok I (don't) see. Interesting info though and I just learned something.

Geoff.



Thanks Barnett and Geoff. I should have first mentioned I have to stick to a long style clutch due to the Yella Terra flywheel.
I just took a look at the YellaTerra website. While it didn't show up, there is a clutch note for factory style to diaphragm conversion, #6173. Perhaps you're not stuck with old technology after al. I would be interested in learning more if anyone has that info. It my come in handy.

Geoff.

 
Last edited by a moderator:
I agree the Zoom is junk.

The Centerforce Dual friction is Okay

The McLeod Sintered iron clutch is very durable and while it has heavy pressure and is expensive @ about 650) it is a great piece. I think they call it the Street extreme, and you'll have to call them as they don't list your application anymore, but I am running one, so I know they were making it as recently as a little over a year ago

The McLeod you listed is little better than stock.

 
Need your help again guys...

I have a Boss 351 modified with headers and intake. I purchased a blow-proof flywheel and new dampener for insurance (plus they are lightened by around 20%) so I can safely drive the car however I want without worries.

I have narrowed down the clutch and pressure plate selection to the four choices linked below.

Which one would you recommend and why? Anyone with personal experience with either one? Thanks in advance.

I am leaning towards the Mcleod in the last link (not because of price but due to its stock application).

1. Zoom Kevlar

http://www.summitracing.com/parts/zzz-hp7350-1/overview/year/1971/make/ford/model/mustang

2. Ram HDX

http://www.summitracing.com/parts/ram-88769hdx/overview/year/1971/make/ford/model/mustang

3. Standard Ram http://www.summitracing.com/parts/ram-92769/overview/year/1971/make/ford/model/mustang

4. Mcleod StreetPro

http://www.summitracing.com/parts/mcl-75111/overview/year/1971/make/ford/model/mustang
If limited to the choices above, I'd select the Ram HDX. Having the sintered metal face on one side improves durability somewhat. Also, I've used Ram products with success in many different applications. A lot depends on the power level and how much abuse you intend to inflict on the clutch. I've used discs with sintered metal material on both sides on the street for many years, I tend to be hard on clutches. They are a bit "on or off" and can cause chatter if the car is geared numerically lower than about 3.73:1. It does take more finesse to be smooth. I tolerate these things because I hate changing clutches. In my experience, the long style clutch is more reliable, shifts better, and is more consistent when shifting at high RPMs than a diaphragm style clutch. The diaphragm style clutch is not new technology but is very popular because they are fine for regular street driving and require less pedal effort to operate. I suggest you contact RAM tell them what you have and how you intend to use it and consider their recommendation. Good luck with the build.

Chuck

 
McLeod Street Extreme, no doubt.

 
Thanks for the replies. I've narrowed it down to 2 choices. Both are McLeod but the SuperStreet Pro. It's a dual friction clutch but one is diaphragm style and the other is a long style.

Long Style

http://m.summitracing.com/parts/mcl-75211

Diaphram style

http://m.summitracing.com/parts/mcl-75212

The first link the pic of the pressure plate is wrong.

I'm also cancelling the Yella Terra flywheel. Just found out McLeod makes a billet flywheel 5lbs lighter than stock. I feel better about sticking with one overall brand.

 
Thanks for the replies. I've narrowed it down to 2 choices. Both are McLeod but the SuperStreet Pro. It's a dual friction clutch but one is diaphragm style and the other is a long style.

the mcleod street disc is not good enough to take much abuse . if you dump the clutch and speed shift etc, i would use a dual friction mcleod or centerforce disc.

don't buy a pressure plate unless you know what the pressure is so you can have an idea on how hard it will be to depress the clutch pedal . if you only subject it to moderate abuse and don't want a heavy clutch pedal, i would use an 1850 lb pressure plate.

mcleod will build a late to your spec if you want.
 
^^ yes. after research I found your advice is what I'm following. Thanks Barnett.

 
I miss driving a manual trans - Our last "new car" was a 2003 Mustang Cobra. Still have it but I can't work the clutch anymore.

My son takes me for rides but he won't drive right. He knows how to bang shift at the red line it cause I taught him how. Now he claims ignorance..... I may threaten to disown him if he does not straighten up. (he is reading this right now and told me not to post this)

McLeod has been around for awhile and I do not remember hearing anything bad about them.

Paul of MO

 
^^ yes. after research I found your advice is what I'm following. Thanks Barnett.
Glad you figured out a plan.

Here's some triva for you.

Mcleod street discs are made in mexico and have strands of asbestos in them, but mcleod doesn't like them as much as the street discs that centerfoce has and was wanting to change them to a material more like the one centerforce uses but it's not practical for them to do that for various reasons.

the centerforce street disc will take a lot of abuse.

we installed 3 zoom clutches on low power v8's and some of the clutch material came off the disc and stuck to the flywheel and pressure plate causing them to chatter after less than 500 miles so we quit selling them

i even took a zoom pressure plate to mcleod and put it on their plate tester and you could EASILY see the thing flex like like tin foil, and this was at around only 1600 lbs of clamping force which is just about what the stock force is on many stock ford pressure plates . i know this because i took several stock plates to mcleod and had them tested.

after i tested the stock plates, i had them make me several that were only around 100 lbs heavier so i could use them in mildly modified cars and still have a light pedal feel . i eventually convinced them to make them for their regular line up.

there should be no more than .015" between the lowest and highest fingers in the pressure . if there is, the clutch might chatter so i got a bunch of shims from mcleod and check every one i get just in case and even if they are at the maximum allowable spec of .015", i shim them so the difference is less . this can easily be done in a couple minutes . if you ask them for some, they may mail them to you.

Anything pressure plate around 2000 lbs or more can cause the z bar to flex and sometimes bend, so if you use a heavy clutch like that, you might consider welding a plate to the side of your z bar to reinforce it.

REINFORCED BAR ON RIGHT

DSC04127_zpsd3b97a48.jpg


Adding a small reinforcing gusset at the base of the arm will help on moderately strong pressure plates but it still wont prevent bending on the strong ones.

100_3765.jpg


.

to

 
Barnett, sure wished I known you when I had my 67 289 4sp Mustang. I was young and tried to kill that car every time I drove it. With my style of driving the weak areas made regular appearances and the necessary upgrades were made. Once all that got sorted out I found a clutch that was way better than the 271-289 clutch I was running. Unfortunately the new problem was it was twisting my Z bar. I noticed that I was picking up a lot of vibration as the bar was trying to twist it and my headers off the car. I replaced several (which was fun with the headers). A friend tried to reinforce one for me but they continued to twist. The ones you've illustrated look like they would have been the perfect fix for my problem! ::thumb::

 
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