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I am in the process of building a new motor (327/350) for my 65. I am going to replace the clutch, pressure plate and flywheel while I am at it. I have ordered the Centerforce II, as it seems it is the aftermarket clutch of choice on this board. My question is, I am considering using a 17 pound lightweight billet steel flywheel and am wondering if I could get some feedback whether this is a good idea, or not. I understand that the lighter flywheel will allow the engine to build rpm's a little quicker than the 30lb stock unit, but I would like to know what to expect when I start from a dead stop, and normal driving. Any feedback would be greatly appreciated, as I only want to do this once....So I want to do it right the first time!!
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Re: Flywheel Question
Dave-----
I don't think that the 12-3/4" flywheel used for all 1963-67 Corvette small block applications was a 30 lb flywheel; I think it was more like about 24 lbs. However, I DO NOT recommend the use of a lightweight flywheel for a street-driven, small block Corvette. Driveability will be impaired, especially the "get-go" from a standing start.
For your application, I recommend flywheel GM #366860. This is a stock weight flywheel of 12-3/4" OD, 153 tooth configuration, as original.In Appreciation of John Hinckley -
Re: use the flywheel
use it, you will love it. i put one in a customers 63 and it works great! he has NO problems with this flywheel. make sure you get it and the pressure plate neutral balanced.Comment
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Re: Flywheel Question
Agree with Joe. A light weight flywheel is NOT the hot ticket for street driving unless you have REALLY short gears.
BTW, Joe, I weighed my OEM '63 flywheel and I recall it was 33 pounds. I considered replacing it with the 18 pound L-88 flywheel, but with a mechanical lifter SHP small block, close ratio four speed, and a 3.08 axle, I decided the heavyweight was the way to go. It's tough enough to get rolling as it is.
And Dave, there have been reports of problems with Centerforce clutches - particularly not being able to get them adjusted before running out of thread on the pedal pushrod. Take a look at the OEM replacement clutches from Luk, Sachs, and Borg-Warner. They are engineered to OEM specs, should provide good service for normal street and highway driving and are probably cheaper to boot.
DukeComment
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Re: Flywheel Question
duke, put some 4:11's in there and you wont have a hard time gettin her going!Comment
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Re: Flywheel Question
I had a '69 Z-28. Stock engine, 4:11 gears and close ratio transmission. I had one of those lightweight L-88 flywheels laying around not being used and I stuck it in there. The engine revved good and sounded good but I would get embarassed at times at a stoplight by killing the engine on take-off. If I drove the car everyday, I would have soon become accustomed to it and it would probably not been a problem. Overall though, not the way to go.
I used a Shiefer lightweight wheel in a '56 Chavy that had a 327/360 engine. This car was geared so ungodly low that first gear was one big lunge to about 35 mph and 7000 on the tach. The light wheel was no problem on this car. This reflects what Duke told you about the gears.
Your choice.Comment
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Centerforce Problems?
Are there many instances with problems with the Centerforce clutches? I have read some pretty positive feedback on them, and have recieved positive feedback from friends that have run them....I would assume that if a new cluth assembly, throwout bearing and new flywheel are installed that have the same thickness as the stock units, then you should have proper adjustment...If there is an inherent problem with the centerforce units and corvettes, I would sure like to know it before I get everything together..Comment
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Re: Flywheel Question
People have ragged on me for over 35 years about my gear choice. I was never into drag racing, so "Sebring gears" were my choice. Other than getting her going I like the easy 80 MPH cruising at 3100, the top speed potential and 22 MPG highway fuel economy.
The fastest sustained cruise I ever did was 130 at 5000 - made if from the California-Nevada border to The Strip in 18 minutes. That was back in '67 before Nevada had speed limits.
Those tall gears are why I will only install "V" or better rated tires on my SWC. You never know when an opportunity to test top speed will crop up, so I'm always prepared.
DukeComment
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Re: Centerforce Problems?
Drop an e-mail to ghostrider20@earthlink.net. He had to pull the Centerforce out of his '65 SHP. Tell him SWCDuke referred you. Mark also hangs out on the Corvette Forum - C1 and C2 Discussion.
DukeComment
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Re: Flywheel Question- Dave
Dave,
In the early '60's I installed a Shaffer aluminum flywheel in my '56. The original engine is bored to 283 and the original rear end is 3.70. I have the close ratio 4-speed. With this combination there are no drivability problems, I guess a little clutch slipping to get rolling up grades, maybe. As your 350 has a lot more torque and if your rear end is 3.70, I would think you wouldn't have any problems. Regards.Comment
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Re: Flywheel Question - Warning
There's one thing I have not seen mentioned in this thread and that is OEM flywheel material. Some GM flywheels were made out of what I believe is called 'gray iron' as opposed to ductile iron. Apparently 'gray iron' flywheels have been known to come apart at high RPMs. I think it's safe to assume all high-perf engines had good flywheels, but I don't know about base engine cars. I wish I could be more specific as to how to go about identifying a gray iron flywheel, but what I do know is if you turn the flywheel over and look at the engine block side, the outside edge is 'thicker' on the ductile iron flywheels and 'thinner' on the gray iron ones. This 'edge' would be the distance from the ring gear in towards the center. At some point the front to back thickness of the flywheel thins based on the casting itself. I wish I had more skill at descriptive writing. The source that spent a fair amount of time making sure I was aware of these lesser flywheels is a gentleman named Red Roberts at McLeod Industries.
RogerComment
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Re: Flywheel Question- Dave
I called Centerforce today, and was told that if all of the factory original, or equivilent replacements are used, ie. correct clutch fork, correct thickness flywheel, correct throwout Brg, ect are used, then there should be no problems whatsoever with the centerforce clutches. Judging from the general thoughts on this post, I think I am going to pass on the lighter flywheel, in fact, I ordered a centerforce billet flywheel that is a little heavier than the stock unit (30lbs vs 26lbs). I am not building a circle track or road racing motor, and I certainly do not have the gearing to support the lighter flywheel. Also, I am being told that the heavier flywheel helps heat dissapation (comes in handy in Vegas), and stores more inertia for a vehicle that is somewhat gear ratio lacking. Thanks again for all of the input!!Comment
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