how many zl1 motors were made

[William]

Do you know if those had YENKO cast into them?

Seen a few like that, one did not have coolant passages.

[JoeC]

The Yenko ZL-1 blocks did not have the Yenko name on them.

On the Winters invoice the ZL-1 blocks have a note - (no trade name)

The Yenko blocks have a note - (with Yenko name plate)

There are photos of two blocks , one has the Winters snowflake and the other block has the letters "YENKO" in the same place where the snow flake is on the other block.

Did the 1969 ZL-1 blocks have a date code like an iron block?
The ZL-1 blocks that Yenko had made would be after 1974 but not sure if they had a date code on them.

There are letters back and forth with Bill Porterfield with an agreement to use and promote the Yenko block. dated Dec 1978 . I know Bill had a company called Mid Engineering and built a mid engine 1978 Olds 442 and a Kelmart GT using Olds engines but may have also used the Yenko block.

[William]

Yes, near the motor mount on the left side. ZL-1 blocks have a casting sequence number, a machining sequence number.

I have a small log of data on blocks that abruptly stops as of July 1969. Have not seen a later casting. They did a pilot run of ZL-1 blocks in the late '80s but used a different, darker alloy. A few of these blocks were machined and built. Somewhere I have a pic of unmachined blocks on a pallet.

Too bad, the entire ZL-1 story may never be told.

[JoeC]

Yenko and Greenwood and others were still using the ZL-1 block in the 1970s for SCCA racing.

I remember an article on Greenwood showing about 15 blocks he had bought from Chevy. There must not have been many new blocks left by the mid 1970s.

[William]

Reason to believe Winters cast just under 600 blocks. Engine production eventually totaled 182: 80 "ME", 14 "MG", 54 "ML", and 34 "MM". I have heard there was a high scrap rate but no hard numbers. No matter, plenty of unused blocks around.

Another observation: have never seen and do not know of a CE ZL-1 short or fitted block. The ZL-1 Camaros I know of that had warranty engine failures were either repaired or had complete engine replacement with a converted ME code engine.

At this time, I do not know of a production ZL-1 Camaro built with a Holley #4296 carb. Some of Gibb's 50 were retrofitted; original owner history on one of the last cars built stated it was delivered with the L72/L78 #4346.