how many zl1 motors were made

[Steve Shauger]

Originally Posted by William

It has historical value.

As for monetary value, ask the people that have been sitting on internal Chevrolet Engineering documentation for decades. Still waiting on the big payday. The people ready to write the book have given up in frustration. The number of people that care is shrinking fast.

As long as the Dog In the Manger act continues, the entire ZL-1 story will not be told.

Very well said William... The poster may be associated with those holding the documents....

[Luke 10:27]

I agree with all of you. The individual associated with these documents originally is long gone. The caretakers of them believe they have high value (I assume was told this by the original source). They are fearful of going public with them as they think there could be legal repercussions as the company is still in business. I believe they would destroy them if they thought they could risk being in trouble. I was brought into this because they trust me and I have knowledge on this stuff. I would like to make sure the historical part is preserved but I am guessing it won't be given away. I am considering making an offer to buy these documents but if I would do that, I would have a way to recoup my investment. If I were a rich man I would buy them and donate them to the historical cause but I'm not a rich man...lol.

[William]

Chevrolet doesn't seem to care much about 53-year-old engineering info. Plenty of Chevrolet engineering documentation was published in the Chevrolet by the numbers books.

Today you can visit the GM Heritage Center and request a part drawing. If they can locate it, they will provide a copy.

I have the 2022 Chevrolet Performance catalog. The ZL-1 block casting is noted: DISCONTINUED-Check dealer stock for availability.

I am curious as to what the difference was between the 3946052 and 3946053 cylinder blocks. Put me down for $20 US.

[Kurt S]

Originally Posted by William

Chevrolet doesn't seem to care much about 53-year-old engineering info.
Today you can visit the GM Heritage Center and request a part drawing. If they can locate it, they will provide a copy.

Agreed. GM does not care about old docs like this - there is no liability or risk here.

GM will not provide copies of prints. If they can find it, you may look at it and take notes.....

[William]

Originally Posted by Kurt S

GM will not provide copies of prints. If they can find it, you may look at it and take notes.....

Chevrolet by the numbers books are full of copies.

[Kurt S]

Originally Posted by William

Chevrolet by the numbers books are full of copies.

Yup, that was then, this is now.

[JoeC]

Chevrolet gave the rights to Yenko to purchase ZL-1 blocks from the Winters Foundry in Canton Ohio. (with some restrictions).

The part number listed is 3952318

The letter is dated June 7 , 1974

signed by F. A. Duco , Director, Manufacturing Sales

[olredalert]

----I have been to the Heritage Center with a good friend and spent a whole day going thru reems of paperwork looking for particular stuff. Found many interesting things so it was a fruitful day. My friend went back and spent the whole next day as well. If there is a good enough reason you can make an appointment!....Bill S

[William]

Chevrolet produced other, different; aluminum big block castings that were not part of the ZL-1 program. Some were never sold to the public, provided to Chaparral and McLaren for their race cars. As of early 1968, they began development of an 'aluminum block L-88' that later became Corvette RPO ZL-1 for the 1969 MY. Due to poor sales, the ZL-1 program ended July 1969.

Chevrolet continued to develop aluminum big block castings for racing without liners or provision for a mechanical fuel pump. These were sold as bare blocks only, never used in production. Those and Yenko blocks are not considered ZL-1s.

The only true ZL-1 castings are 3946052 and 3946053, as used in 2 production Corvettes and 69 Camaros.

[JoeC]

looking at the Yenko documents it looks like they bought about 200 of the ZL-1 blocks from the Winters Foundry after 1974.

These were required by SCCA for the Corvettes that ran the ZL-1 engine.

The other Yenko aluminum blocks were not legal to race in the SCCA Corvettes at that time.

Zora and Vince Piggins were involved with getting the blocks made.

The part number 3946052 is listed as the "cylinder and case rough "

The part number 3952318 is for the "cylinder and case assembly "

The 3952318 assembly has a parts list of about 20 parts including bearing caps and bolts, plugs, dowel pins , cam plate, and other small parts.

These Yenko documents are in the Mark Gillespie 2nd Yenko Era book. Includes a hand written note from Vince Piggins.