Choosing a new clutch

[Paul G]

The new engine is going in soon, need to pick a clutch to go behind it. There are many to choose from. It is a 73 Charger, 4000# car, 323 rear gear, new 505ci engine, estimate 550+ HP 600+ TQ. This engine may not stay in this car for ever. The car will most likely get a 450HP engine later when the 505 goes to it's permanent home. Street use 99% of the time with a yearly trip to the drags. Street driving with street tires, but it will be aggressive on the street with either engine.

The clutch that came out was a 10.5" diaphragm style. It was smoked, the flywheel had lots of cracks and many black spots. That was with a stock 383 and who knows how it was treated.

Borg and beck style vs. diaphragm?
10.5" or 11"?
Single disc or dual disc?   

I dont know much about clutches?

[c00nhunterjoe]

I ran an 11" centerforce dual friction in my car for years with daily abuse on sticky tires. Loved it. Soft pedal feel, very responsive. Ran them in several stick cars over the years. Never had a failure or issue with slicks. Others hate them. I think you will find a love/hate with every brand and style. I think in your case a dual disc is overkill.

[Paul G]

Is the bell housing different between a 10.5" and an 11" clutch?

This Hays 10.5" clutch is rated for over 500 HP. Borg and Beck style. I guess that means the spring on the clutch pedal needs to be there right?

Hays clutch     https://www.summitracing.com/parts/hay-85-301 

[c00nhunterjoe]

Yes, you still need the pedal spring with the factory style clutches.

[XH29N0G]

I ran an 11" centerforce dual friction in my car for years with daily abuse on sticky tires. Loved it. Soft pedal feel, very responsive. Ran them in several stick cars over the years. Never had a failure or issue with slicks. Others hate them. I think you will find a love/hate with every brand and style. I think in your case a dual disc is overkill.

I am using the centerforce dual friction and like it.  I didn't respond immediately because I have less than 10000 miles on it and don't know the size.  So far it works well. 

[Paul G]

Borg and Beck vs. diaphragm style? Is there a preference?

[XH29N0G]

See what other people say.  I had heard that there were differences that should be considered (B&B, centrifugal, and diaphragm) from some people when I was shopping, but the person who was doing my restoration said they had good experience with the centerforce (diaphragm) and that the power level was OK for that one.  I thought I would try it.   

I had used Borg and Beck before and had one clutch disk fail in the 1980's (it wasn't old and I don't know why. The rivets stuck out.  Maybe I was riding it, or missed something else.  Maybe the quality was an issue.)

The main thing they said was the scatter shield which doesn't look stock, but is another think I have been happy to try. So far so good. 

I have a few other thoughts.  I don't think I am super hard on the clutch I have and even though the engine is healthy and I have been to the drag strip, I have 4.30 gears which also eases the demand on the clutch. 

[Paul G]

I have been reading that a dual friction clutch on the street may chatter and be a little "grabby", more difficult to get the car moving. You may not experience that with your gearing? I have 3.23 gears, it is mainly a street car. What is your experience been?

[XH29N0G]

As you said, my gearing is different,  I have seen no chatter.  On a rare occation I accidentally start in third (I;m the one on the right).  I have not noticed chatter then.

BUT one person not seeing it and a bunch saying they see it probably means it is a real phenomenon.

[c00nhunterjoe]

90% of th3 clutch chatter cases i see are flywheel related. Ie not machined before install or machined improperly  and hot spots form. Ive had dozens of dual frictions in cars over the years without chatter and have not had complaints from any friends who run them either. Its a good moderate hp clutch with a soft pedal for daily driving.

[Paul G]

Question; am I limited to the 10.5" clutch with my aluminum bell housing and 130 tooth flywheel? To use an 11" clutch I would need a 143 tooth flywheel, right? Will that fit in the aluminum bell housing I have?   

[Paul G]

I ran an 11" centerforce dual friction in my car for years with daily abuse on sticky tires. Loved it. Soft pedal feel, very responsive. Ran them in several stick cars over the years. Never had a failure or issue with slicks. Others hate them. I think you will find a love/hate with every brand and style. I think in your case a dual disc is overkill.

Do you know what bell housing you used?

[Paul G]

Thinking about bell housing's and fly wheels. The starter is bolted in a fixed position on the bell housing. The starter must be in the right location to engage the teeth on the flywheel. A 130 tooth flywheel will have smaller diameter than a 143 tooth flywheel. Unless my thinking is all screwed up, the flywheel and bell housing must match, or the starter will not engage the flywheel correctly.

Right or wrong? 

[70sixpkrt]

Is it a 18 or 23 spline?

[Paul G]

23 spline

[70sixpkrt]

http://www.brewersperformance.com/category09.php

[70sixpkrt]

I personally don't like the diaphragm setup. I think it's too soft and my foot feels like it will go thru the floor board. I would go for a Ram Borg and Beck 10.5 23 spline clutch. If you want to stick with diaphragm, then go with a Mcleod MC75209.

[c00nhunterjoe]

I ran an 11" centerforce dual friction in my car for years with daily abuse on sticky tires. Loved it. Soft pedal feel, very responsive. Ran them in several stick cars over the years. Never had a failure or issue with slicks. Others hate them. I think you will find a love/hate with every brand and style. I think in your case a dual disc is overkill.

Do you know what bell housing you used?

I do not recall the pn offhand but i ran a stock aluminum housing at 1st and then changed to a lakewood blowproof.

[Paul G]

I called and talked with McLoed today. The guy said the single disc clutches will not hold up to the stroker motors torque. I estimate around 600 Ft#'s. He recommends the dual disc set up. Part #6913-02. Both disks are organic for normal clutch pedal feel, but will handle 800FT#'s. 

All in this will be a $1250 clutch. OUCH.

[66FBCharger]

I called and talked with McLoed today. The guy said the single disc clutches will not hold up to the stroker motors torque. I estimate around 600 Ft#'s. He recommends the dual disc set up. Part #6913-02. Both disks are organic for normal clutch pedal feel, but will handle 800FT#'s. 

All in this will be a $1250 clutch. OUCH.

Does the dual clutch set up require a special flywheel? If so, is the flywheel included in the $1250 price?

[Paul G]

I called and talked with McLoed today. The guy said the single disc clutches will not hold up to the stroker motors torque. I estimate around 600 Ft#'s. He recommends the dual disc set up. Part #6913-02. Both disks are organic for normal clutch pedal feel, but will handle 800FT#'s. 

All in this will be a $1250 clutch. OUCH.

Does the dual clutch set up require a special flywheel? If so, is the flywheel included in the $1250 price?

I dont know if the flywheel is specific to that clutch. I dont think so since it has it's own part number. Yes, every thing I need is included in that price.

[XH29N0G]

One thought, and others will correct if I am wrong because I really do not know what I am talking about.  You mention aluminum bell housing and significant torque numbers and are asking about flywheels.  If it were me, I would ask whether you are at the point where you should be looking at a flywheel that was as unlikely to blow apart and some a blowproof scattershield. 

[70sixpkrt]

https://www.summitracing.com/parts/mcl-6913-02
$752 from Summit. Flywheel not included. Good setup.
https://www.summitracing.com/parts/mcl-464102
Flywheel $314. I bought that flywheel a couple of years ago.

My buddy is using that setup in his 68 Hemi GTX with 670hp. He is using a Lakewood scatter shield.

[Paul G]

One thought, and others will correct if I am wrong because I really do not know what I am talking about.  You mention aluminum bell housing and significant torque numbers and are asking about flywheels.  If it were me, I would ask whether you are at the point where you should be looking at a flywheel that was as unlikely to blow apart and some a blowproof scattershield.  

You are thinking correctly. That is why I am not reusing the stock flywheel and buying a new one to match the clutch.

https://www.summitracing.com/parts/mcl-6913-02
$752 from Summit. Flywheel not included. Good setup.
https://www.summitracing.com/parts/mcl-464102
Flywheel $314. I bought that flywheel a couple of years ago.

My buddy is using that setup in his 68 Hemi GTX with 670hp. He is using a Lakewood scatter shield.

That is the set up. TO bearing, new bolts, it adds up quickly.

[Paul G]

So this is whats got me a little hesitant to go for the $752 bad ass dual disc clutch. The stroker is not going to be in this car forever. At least that is not the plan. My 72 is what I built the stroker engine for. It has an automatic. The 383 is going back in the 73 after I refresh it. It will be about 400 HP.  The $411 Super Street Pro dual friction can easily handle that, but it will be at it's hairy limit behind the stroker. What to do?

Edit; Unless I stroke the 383 and put it in the 72.