LUK 04-049 clutch kit

[Patrick B.]

I am trying to find the best currently available clutch equivalent in clamping force and quality to the original clutch of my 70 LT-1. I have seen recommendations of LUK clutches here because they are made by an OE supplier. The 04-049 part number is supposed to be an 11” clutch with a 10 spline disc. But when I enter my car description in Summit, Rock Auto and other seller web sites, they warn that it does not fit my car. Rock Auto seems to think 70 Corvettes have 10 1/2 “ clutch’s. Even when I enter 67 427 Corvette which should definitely call for an 11” clutch, the web sites say it does not fit. Has anyone here used this part number clutch. The GM parts book lists the stock 11” clutch has having about 2600 lb clamping force. In stumbling around the internet pursuing LUK clutches I may have seen the mention of 1700 lb clamping force, but I can’t find it again. Could it have that much less clamping force than an original clutch?

[Joe L.]

Re: LUK 04-049 clutch kit

I am trying to find the best currently available clutch equivalent in clamping force and quality to the original clutch of my 70 LT-1. I have seen recommendations of LUK clutches here because they are made by an OE supplier. The 04-049 part number is supposed to be an 11” clutch with a 10 spline disc. But when I enter my car description in Summit, Rock Auto and other seller web sites, they warn that it does not fit my car. Rock Auto seems to think 70 Corvettes have 10 1/2 “ clutch’s. Even when I enter 67 427 Corvette which should definitely call for an 11” clutch, the web sites say it does not fit. Has anyone here used this part number clutch. The GM parts book lists the stock 11” clutch has having about 2600 lb clamping force. In stumbling around the internet pursuing LUK clutches I may have seen the mention of 1700 lb clamping force, but I can’t find it again. Could it have that much less clamping force than an original clutch?

Patrick------

Well, they're all correct about the LUK 04-049 clutch kit being incorrect for your 1970 LT-1 assuming that your LT-1 is part of the ZR-1 package. However, if your LT-1 is not part of the ZR-1 package, then the 04-049 is the correct kit and it will work just fine.

For some reason I've never figured out, there is a lot of misinformation out there regarding clutches for 1969-74 Corvettes. However, it's actually like this: ALL 1969-74 Corvette small blocks, except ZR-1, were equipped with a 14" flywheel and 11" clutch. Only ZR-1 was equipped with a 12-1/2" flywheel and 10.4" clutch ("sort of" LUK 04-021). You can take this info "to the bank".

By the way, I should have mentioned, the original pressure plate assembly was GM #3893236 and after December, 1971 GM #3884598. The clutch disc was GM #3908960.

All 1970 and earlier clutch friction discs were 10 spline. All 1971 and later clutch discs except 1978 L-48 were 26 spline. The LUK 04-049 kit has a 14" friction disc with 10 spline.

[Peter M.]

Re: LUK 04-049 clutch kit

Pat,
I have the 04-049 in my 67. I have had no problems with it.
Just a FYI, the throughout bearing that comes with it is some type of composite material.
Kind regards

[Patrick B.]

[Joe L.]

Re: LUK 04-049 clutch kit

Pat,
I have the 04-049 in my 67. I have had no problems with it.
Just a FYI, the throughout bearing that comes with it is some type of composite material.
Kind regards

Peter------

The 04-049 the right one for 1967 big blocks (except L-88). It's not the right one for 1967 small blocks.

[Joe L.]

Re: LUK 04-049 clutch kit

Thanks Joe and Peter— I have heard that the composite TO bearings work fine, but I have an all steel made in USA 1 1/4” TO bearing I plan to use with it. I hope there is no reason an old style bearing will not work.

Patrick------

The old style release bearing will work fine with the LUK clutch.

[Peter M.]

Re: LUK 04-049 clutch kit

Joe,
Yes, I should have specified my car is a 390 hp 427.
Kind regards

[James G.]

Re: LUK 04-049 clutch kit

Patrick,
I have used LUK on at least the last 5-6 stock replacements or restorations and have zero issues with them.
The centerforce clutch is the one I always use if I am looking for a streetable HIGH performance clutch with max clamping force. Not cheap- at least double the LUK, but well worth the money if you are running something which needs a really high clamping force.

[Patrick B.]

Re: LUK 04-049 clutch kit

James- I already have a McLeod street/strip clutch which has been with the ZL-1 for almost 40 years. It works fine but it takes so much petal force that I am ready for a stock clutch when I re-install the LT-1.

[James G.]

Re: LUK 04-049 clutch kit

Thats the thing with the Centerforce, my 110 pound ex-wife could easily push it in.