1969 Corvette Original Clutch for the 350/350 Engine

[Larry M.]

I am helping a friend restore his late 1969 Corvette, built the last week of production. It has a 350/350 engine and 4-speed transmission.

The engine was rebuilt by a restoration shop/engine shop and returned to my friend with flywheel, clutch disc, pressure plate, and bell housing installed. The engine was run and broken- in on the shop dyno, so it should be ready to install and go.

A quick check by me showed a straight finger pressure plate and a long throw-out bearing. When I questioned this, the shop owner stated that the pressure plate and disc were as factory original and correct for the 350/350 engine. To the best of my knowledge, all C2 Corvettes and I presume all 68-69-70 C3 Corvettes had the "bent finger diaphragm pressure plate from the factory and the short throwout bearing.

Looking for some help on whether the shop owner knows something I do not, or if the correct clutch for the 69 350/350 engine should be a "bent finger" design. From my early hot rodding days, the straight finger diaphragm clutch was for the lower RPM passenger car applications and not installed in Corvettes. I certainly would not think Chevrolet would use it behind the 350/350 HP engine.

My checks in the Chevrolet Corvette Parts Manuasl show a "bent finger" design listed for C2 and C3 cars.

Not certain about the manufacturer of this clutch, but I believe it is Sachs.


Larry

[Michael L.]

Re: 1969 Corvette Original Clutch for the 350/350 Engine

Larry,

Here are a couple of pics of the clutch and TOB I installed in my 69 350/350. Not sure what factory was but this is what was recommended to me to be the closest to stock available. Hope it helps.

Mike

[Larry M.]

Re: 1969 Corvette Original Clutch for the 350/350 Engine

Mike:

Thank you for the quick response. Yes, what you show is what I would expect to see. But that is not what is on the engine currently.

Is your clutch a LUK?? Or another brand??

Thanks again.

Larry

[Joe L.]

Re: 1969 Corvette Original Clutch for the 350/350 Engine

I am helping a friend restore his late 1969 Corvette, built the last week of production. It has a 350/350 engine and 4-speed transmission.

The engine was rebuilt by a restoration shop/engine shop and returned to my friend with flywheel, clutch disc, pressure plate, and bell housing installed. The engine was run and broken- in on the shop dyno, so it should be ready to install and go.

A quick check by me showed a straight finger pressure plate and a long throw-out bearing. When I questioned this, the shop owner stated that the pressure plate and disc were as factory original and correct for the 350/350 engine. To the best of my knowledge, all C2 Corvettes and I presume all 68-69-70 C3 Corvettes had the "bent finger diaphragm pressure plate from the factory and the short throwout bearing.

Looking for some help on whether the shop owner knows something I do not, or if the correct clutch for the 69 350/350 engine should be a "bent finger" design. From my early hot rodding days, the straight finger diaphragm clutch was for the lower RPM passenger car applications and not installed in Corvettes. I certainly would not think Chevrolet would use it behind the 350/350 HP engine.

My checks in the Chevrolet Corvette Parts Manuasl show a "bent finger" design listed for C2 and C3 cars.

Not certain about the manufacturer of this clutch, but I believe it is Sachs.


Larry

Larry------


The shop owner is absolutely incorrect. I absolutely guarantee it. ALL 1969-80 Corvettes (except L-88/ZL-1/ZR1) were originally equipped with pressure plate assembly GM #3884598. This is an 11" BENT FINGER design. Originally, this was used with a release bearing of 1-7/32" length. This was later replaced with a 1-1/4" bearing and I don't think the 1-7/32" bearing has been manufactured for many years by any source.

C2 Corvettes also used the "bent finger" design and "short" release bearing but, as far as small blocks, L-78, and L-88 go, all used a 10.4" pressure plate assembly. 1966-67 big blocks used the same clutch set-up as all 1969-80 Corvettes.

The only Corvette that EVER used the 1-7/8" "long" type release bearing was early 1955. ALL Corvettes thereafter use the "short" type bearing.

I have seen this notion that Corvettes used straight finger pressure plates and "long" style release bearings many time before. Somehow, it seems to be ingrained in the minds of many in the automotive business. Regardless of how otherwise expert they might be, they are DEAD WRONG on this belief. Absolutely. Positively.

By the way, I should also have mentioned that any automotive reference, including and especially aftermarket parts manuals, which specify a straight finger pressure plate and/or a "long" style release bearing is incorrect. Period.

[Larry M.]

Re: 1969 Corvette Original Clutch for the 350/350 Engine

Thank you Joe. Your reply is just about the exact words I have used with my friend. However, the shop owner has a different story, and further states that changing the the clutch assembly will cancel the engine and driveline warranty that he provides.

It is my friend's car and my friend's money. He also needs the warranty going forward. But as the "Corvette Consultant" and also a "line worker" on this restoration job, I do not want to install the current engine and driveline and then a few months later have to do it all over again because things are not right. I also do not want to confront the shop owner on behalf of my friend without being 150% correct on what I say.

Appreciate both your and Mike's help on this issue. Again, thank you.

Larry

[Michael L.]

[Michael L.]

[Dick W.]

Re: 1969 Corvette Original Clutch for the 350/350 Engine

Most likely if that car was manufactured today it would have a LUK clutch in it. They are OEM suppliers to many manufacturers