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67 Camaro L78 M20 Convertible
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Discussion Starter #21 (Edited)
I'M thinking about replacing the clutch in process of engine installation. Since its a new flywheel, too.

I have a Muncie M-20:

Casting: 3925660 Years: 1968 - 1970 Ratios: M20 2.52 1st , M21 2.20 1st, M22 2.20 1st
No lower drain plug (introduced early 1969 and later), so probably a early 1969 muncie.
3857584 tailshaft housing, which means “Passenger-Side-Mounted Speedometer, 27 Spline.
And all 10 spline inputs came with 27 spline output shafts.
Main Caseside coverTailshaftSerial Nr
3925660​
3950306​
3857584​
P9D14A = 1969 April 14 M20

So i am looking for a 10-Spline 11" clutch for a 168 tooth flywheel, capable of 670hp with street tires.

I summited that specs, and out came this candidate:

1967 CHEVROLET CAMARO McLeod Street Extreme Clutch Kits 75324

--> We recommend it for cars up to 700 crank Hp/Tq with moderate engine mods and street tires.

Brand:McLeod Racing
Manufacturer's Part Number:75324
Part Type:Clutch Kits
Product Line:McLeod Street Extreme Clutch Kits
Summit Racing Part Number:MCL-75324
UPC:887753010902
Clutch Usage: Performance
Clutch Disc Quantity:Single
Input Spline Quantity:10
Input Shaft Diameter:1.125 in.
Disc Diameter (in):11.000 in

Was already used in the forum:

I guess thats a good choice.. ?!
 

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I'M thinking about replacing the clutch in process of engine installation. Since its a new flywheel, too.

I have a Muncie M-20:

Casting: 3925660 Years: 1968 - 1970 Ratios: M20 2.52 1st , M21 2.20 1st, M22 2.20 1st
Since you are that far I would agree. Really with what you are doing you might want to go through the trans also. One basically new drive train.
 

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67 Camaro L78 M20 Convertible
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Discussion Starter #23
Now i am rethinking:
Still ceramic clutch,
& still good for "up to 20-60% more torque".
My engine is 35% more torque than stock LS6 BBC, so its right in the window.

And what i also like:

"Specifically for '60s and '70s American muscle cars with mechanical linkages" and that is exactly my case..

And also its half the price. Since i need to change clutch again when upgrading to tko 600 in a few seasons (probably less than 10k miles away) cause of 26 splines instead of 10, i think its a little overkill with the mcleod.

Zoom 30000 Series Clutches 30015

Now i try to find some experience about those clutches..

What i also see: 6 smaller instead of 5 springs around the center. Wonder what that is all about.. ?
 

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67 Camaro L78 M20 Convertible
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Discussion Starter #24 (Edited)
And now i found this:

Hi,
Yes & No. I called Zoom this morning and spoke to a tech guy. I explained the entire situation and he told me that he "cringed" when I told him the Zoom clutch set part number ZZZ-30015. This is the clutch set up I bought from Summit Racing. Zoom told me this clutch set is a ceramic racing clutch and not advisable for street use. He said my clutch chatter will not get better because the clutch is designed fir high RPM take off so that is why it is chattering in 1st gear under normal load. He told me I need Zoom part number ZZZ-30006. I called Summit and they told me to send the clutch back and they will send me a 30006 with no charge. I was very impressed with that! I live in Alaska and my wife & I are leaving on the ferry tomorrow for Bellingham, Wa. We arrive on Friday morning and then we are heading down to Puayllup for the Goodguys car show/ drag racing. Since learning that I have a racing clutch, I have been using more RPM on take off which helps cut down and sometimes eliminates the chatter but it is not very good on the stock rear end and Im affraid people think Im either a show off or I can't drive! Ha!
GW


And i also found this, regarding zoom´s HP line:

4 speed guru's

look into the Zoom HP5505-1 or the HP5552-1 clutch kits for your car. both kits are 11" diaphram style clutch with a full kevlar discs for a low coeficient of friction. the only difference between these 2 part numbers is that the 5505 have a 2200LBS static pressure plate while the 5552 has a 2800LBS static pressure plate that gives it s higher clamp load....if yo uhave a 26 spline main counter shaft add the letter A to the end of the part number...check out there website www.zoomclutch.com for more details and use there there caculator to figure out how much torque the clutch will hold so you know which matches your cars torques output for your application....the HP5505 has a maxium torque of 725lbf while the HP5552 has a maxium torque of 923lbf ....

But i also thinkg about this - espacially with my M-20:

Clutch 101: Getting a Grip on Performance Clutches

OE’s intentionally specify clutch systems with a lesser torque-holding capacity than could be possibly generated by the engine; this is to protect the more expensive and harder-to-replace drivetrain parts that could suffer as a result of hard or abusive driving.

So in the end.. i will probably go with a stock clutch. To protect the weak M-20..

like this one:

 

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This clutch has good street manners. You are pushing the torque limit but it should be OK for street tires. Unfortunately I believe you can NOT buy a 26 spline disc separately in the future. They only come as a set. For your amount of torque only a twin disc "Street" clutch will work with sticky tires. There are single disc racing clutches but not great for the street.

 

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Discussion Starter #27
This clutch has good street manners. You are pushing the torque limit but it should be OK for street tires. Unfortunately I believe you can NOT buy a 26 spline disc separately in the future. They only come as a set. For your amount of torque only a twin disc "Street" clutch will work with sticky tires. There are single disc racing clutches but not great for the street.

thanks for the info! This time i will stay with a stock LUK clutch to protect the muncie. With the TKO in the future i will go with a perfomance clutch like you showed..
 

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Discussion Starter #28 (Edited)
After back and forth i now decided to upgrade the carb.
From 750 Edelbrock to AED 850 HO Annular

AED Performance 850HO-Annular

So this "Bottleneck" should be gone, only the exhaust (2.5" dual) is stilll holding back roundabout 5% power between 3.5k-6.5k rpm compared to 18" header extensions as i suspect comparing my setup to Enginemasters 2.5"vs3.0"vs.18"-Header-Ext. Test...

Both mandrel bend systems with straight through mufflers.
At peak rpm, difference is only 17hp (618 vs 601).
But all the way from 3500 up, esp. between 5-5.5k, difference appears to sometimes be double that, i guess 30-35hp (~5%).
This is also indicated by the peak torque difference of 29 LbFt (583 vs 554) (~5%).
The torque difference is pretty steady between 3.5k and 5.5k rpm


267869
 
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