1965 396 - Clutch Replacement

[John Mathieu]

I am at the point where I have prepared the guider bolts as John Hinckley described in a previous thread, linkage is off, engine is supported w/jack, shifter is out and rear drive shaft is disconnected.

Time to order the clutch replacement. I can see from previous messages the Centerforce II is the route to go. Centerforce's online catolog only gives an option for a 1965-1968 5.4L 327 ENG. Can anyone tell me exactly what I will need to order for a complete clutch replacement? Thanks in advance.

[Joe L.]

Re: 1965 396 - Clutch Replacement

John------

The clutch assembly which Centerforce has available for the 63-68 327 application should work for your 396 as well. This will be a 10-1/2" disc and pressure plate assembly. The disc should have a 10 spline, 1-1/8" input shaft hub. Basically, all you need for a clutch replacement is the pressure plate assembly, friction disc, and clutch release bearing. I believe that Centerforce sells the clutches as complete assemblies which also include the release bearing. You should also replace the pilot bushing in the crankshaft end. An original-style bronze bushing is available under GM #10125896 or you can install the roller bearing type available under GM #14061685.

The only other part that you may require is a flywheel. If yours has badly worn teeth on the ring gear or if it has already been surfaced previously and now requires it again, then I'd suggest a new flywheel. In fact, I won't even use a flywheel that's been surfaced even once; I replace them. A very excellent replacement for your application is available from GM under GM #14085720.

[Joe L.]

Re: 1965 396 - Clutch Replacement

John------

The clutch assembly which Centerforce has available for the 63-68 327 application should work for your 396 as well. This will be a 10-1/2" disc and pressure plate assembly. The disc should have a 10 spline, 1-1/8" input shaft hub. Basically, all you need for a clutch replacement is the pressure plate assembly, friction disc, and clutch release bearing. I believe that Centerforce sells the clutches as complete assemblies which also include the release bearing. You should also replace the pilot bushing in the crankshaft end. An original-style bronze bushing is available under GM #10125896 or you can install the roller bearing type available under GM #14061685.

The only other part that you may require is a flywheel. If yours has badly worn teeth on the ring gear or if it has already been surfaced previously and now requires it again, then I'd suggest a new flywheel. In fact, I won't even use a flywheel that's been surfaced even once; I replace them. A very excellent replacement for your application is available from GM under GM #14085720.

[Mark Ring]

Re: 1965 396 - Clutch Replacement

John,
the Centerforce II you mentioned is sold A-La-Carte (?) in 3 individual pieces. The Centerforce Dual Friction is sold as a matching pair of pressure plate and disk. Either way you will need to buy the bearing separately. The part number for the Dual Friction assy is DF271675 and the bearing is N-1716. Centerforce II numbers are CFT361675 for the pressure plate and 383271 for the disk, N1716 is for the bearing.

-Mark.

[Mark Ring]

Re: 1965 396 - Clutch Replacement

John,
the Centerforce II you mentioned is sold A-La-Carte (?) in 3 individual pieces. The Centerforce Dual Friction is sold as a matching pair of pressure plate and disk. Either way you will need to buy the bearing separately. The part number for the Dual Friction assy is DF271675 and the bearing is N-1716. Centerforce II numbers are CFT361675 for the pressure plate and 383271 for the disk, N1716 is for the bearing.

-Mark.

[John Mathieu]

Re: 1965 396 - Clutch Replacement

Any advantages of the bronze bushing vs the roller bearing type?

[John Mathieu]

Re: 1965 396 - Clutch Replacement

Any advantages of the bronze bushing vs the roller bearing type?

[Joe L.]

Re: 1965 396 - Clutch Replacement

John------

The bronze pilot bearing is what was originally used in all Corvette engine applications. It works quite well and lasts a long time. The main advantage is that this type of bearing is tolerant to SLIGHT misalignment of the transmission/bellhousing.

The roller pilot bearing was originally used in certain GM passenger car diesel engine applications. However, its sizing is the same as the bronze bearing so it can be used as a direct replacement. GM recommends this bushing for high performance applications (although GM never used this bearing in any PRODUCTION high performance application). This bearing has a higher load carrying capacity than the bronze bearing and it is virtually wear-resistant. Its main disadvantage is that it is less tolerant of any transmission/bellhousing mis-alignment.

Achieving perfect transmission/bellhousing alignment with the pilot bearing bore is a very difficult task and is rarely performed, or even checked, in SERVICE. Therefore, I think that the bronze bearing is the way to go in most applications.

[Joe L.]

Re: 1965 396 - Clutch Replacement

John------

The bronze pilot bearing is what was originally used in all Corvette engine applications. It works quite well and lasts a long time. The main advantage is that this type of bearing is tolerant to SLIGHT misalignment of the transmission/bellhousing.

The roller pilot bearing was originally used in certain GM passenger car diesel engine applications. However, its sizing is the same as the bronze bearing so it can be used as a direct replacement. GM recommends this bushing for high performance applications (although GM never used this bearing in any PRODUCTION high performance application). This bearing has a higher load carrying capacity than the bronze bearing and it is virtually wear-resistant. Its main disadvantage is that it is less tolerant of any transmission/bellhousing mis-alignment.

Achieving perfect transmission/bellhousing alignment with the pilot bearing bore is a very difficult task and is rarely performed, or even checked, in SERVICE. Therefore, I think that the bronze bearing is the way to go in most applications.

[Clem Z.]

Re: 1965 396 - Clutch Replacement

stay with the bronze one to save your self trouble because joe is correct about the alignment.you can remove the old bushing by threading a 5/8 tap into the bushing and keep turning it till it forces the old bushing out,as it will bottom out in the crank and move the bushing out as you keep turning the tap in.

[Clem Z.]

Re: 1965 396 - Clutch Replacement

stay with the bronze one to save your self trouble because joe is correct about the alignment.you can remove the old bushing by threading a 5/8 tap into the bushing and keep turning it till it forces the old bushing out,as it will bottom out in the crank and move the bushing out as you keep turning the tap in.

[John Mathieu]

Re: 1965 396 - Clutch Replacement

I called the Centerforce Rep. He is agreed with the part numbers you gave me: CFT361675 for the pressure plate and 383271 for the disk. He wanted to double check because he didn't see that specific engine (396) in the list so he called Centerforce Directly. They told him to go with the 1966 427 pressure plate CFT361739. Do you see any areas of concern if I go with the 427 pressure plate?

[John Mathieu]

Re: 1965 396 - Clutch Replacement

I called the Centerforce Rep. He is agreed with the part numbers you gave me: CFT361675 for the pressure plate and 383271 for the disk. He wanted to double check because he didn't see that specific engine (396) in the list so he called Centerforce Directly. They told him to go with the 1966 427 pressure plate CFT361739. Do you see any areas of concern if I go with the 427 pressure plate?

[Joe L.]

Re: 1965 396 - Clutch Replacement

John------

I see a MAJOR area of concern if you were to use a 1966 big block pressure plate/friction disc. All 1966 Corvettes with big block used a 14" flywheel and 11" clutch. These were designed for use with a bellhousing designed to accomodate the 14" flywheel. In fact, 1966 used a unique-to-1966 '444' bellhousing (although it is functionally interchangeable with the '621' used from 1967-81).

1965 Corvettes with L-78 used a 12-3/4" flywheel with a 10-1/2" clutch. These were used with a '403' (or '383') bellhousing designed to accomodate a 12-3/4" flywheel. A 14" flywheel will not work with a '403' bellhousing. However, and for those who are interested, you can use a 10-1/2" clutch with a 14" flywheel/'621' bellhousing IF you have a dual-drilled flywheel.

In your case, you will not be able to use a 1966 Corvette big block clutch with your 1965 L-78 equipped with '403' bellhousing and 12-3/4" flywheel. You could use the 1966 clutch, though, if you change your flywheel and bellhousing. But, you probably don't want to do that.

[Joe L.]

Re: 1965 396 - Clutch Replacement

John------

I see a MAJOR area of concern if you were to use a 1966 big block pressure plate/friction disc. All 1966 Corvettes with big block used a 14" flywheel and 11" clutch. These were designed for use with a bellhousing designed to accomodate the 14" flywheel. In fact, 1966 used a unique-to-1966 '444' bellhousing (although it is functionally interchangeable with the '621' used from 1967-81).

1965 Corvettes with L-78 used a 12-3/4" flywheel with a 10-1/2" clutch. These were used with a '403' (or '383') bellhousing designed to accomodate a 12-3/4" flywheel. A 14" flywheel will not work with a '403' bellhousing. However, and for those who are interested, you can use a 10-1/2" clutch with a 14" flywheel/'621' bellhousing IF you have a dual-drilled flywheel.

In your case, you will not be able to use a 1966 Corvette big block clutch with your 1965 L-78 equipped with '403' bellhousing and 12-3/4" flywheel. You could use the 1966 clutch, though, if you change your flywheel and bellhousing. But, you probably don't want to do that.