ZL-1 casting dates

[GMH454]

Have been lurking on the board for a while but have never seen a listing of the ZL-1 casting dates (the ones cast in the blocks )
If there is a list can someone point me in the right direction.

On another thread we have the following dates :-
2.4.69
6.8.69

If this is not listed elsewhere can anyone add to these
Also presume this is MM/DD/YY

[GMH454]

So that either means that these dates are the only known dates ?????

Or no-one else has any idea .

[rpoz11]

Hhmmmm...Well, please assume that most who deal in these are private collectors; These blocks obviously were ran from late 1968 through what maybe June/July of 1969; this is my guess for the Camaro & couple of Vette cars but one can only guess as to when GM actually poured all of these; either as demand called for it or...? Anyways, I'm sure Cuneen would be the one to offer the best assistance on this...

[GMH454]

My understanding when talking to a former NCRS Chairperson who worked at GM was that they were cast in batches of 300 and had poresity or casting problems with a large proportion of the blocks.

Now I have no idea how long it takes to cast a block, (anyone know ????) but if casting this batch took a couple of days, When this was done did they change the casting date of the batch or leave it with the first days casting date. They changed the casting number each time, but did they change dates ??

Considering only 71 went into cars, the above still gives us a lot of blocks.

Now considering how hard it was for GM to sell these cars, I don't think they were interested in putting a big stock of these in storage ....just in case someone had a lazy couple of grand and dreams of winning Le Mans.

If we could work out how many batches were cast we might have an idea of the number of blocks made. (ask that question everywhere I go )

Considering what collectors pay for the cars I find it interesting that we don't know more about the engines.

Thanks for the reply anyway.
Rgds Terry

[rpoz11]

So far as I can tell, These were initially intended for racing purposes from the start. I would bet by late 69, most in NHRA or World sponsored teams racing these found they did not withstand the extreme demands of all out racing. I think the last use of these were 70 to early 71 on a few select teams, & I couldn't even guess as to how many were used in the Marine racing circles. Who knows! Hard to guess when these fully caught on and probably difficult to obtain much after July of 69. Ironically, it can be seen that our Hobby has endured the long haul with respect and dignity due to the successes that the cast iron blocks provided us then as well as still today!

[KevinC]

If you are still looking for casting dates, I have one of these blocks and the casting date is 4 1 69. Hope this helps.
Kevin C.

[GMH454]

Thank you kevin every bit helps.
Welcome, glad you have come on board.
Can you please fill in your profile, it keeps the folks here happy.

[Eddie M.]

here's one for you

[KXW]

I own a 052 block dated 19 Mar 69. I'm going by memory here, I believe the number below the date code is #266. Hope this information help?

[KevinC]

The 052 block that I own has a casting date of 4 1 69. The number that is cast below it is "257". On the back of the block, on the machined boss at the top of the bellhousing flange the number "498" has been stamped in and the number "498" is stamped into all the main caps. It has never been decked and there was never anything stamped on the front pad. This block is standard bore and was only used approximately 2,000 to 3,000 street miles in it's entire life. It has been sitting for a very long time and is in almost NOS condition.