Engine Block Assembly Date Code

[S7MS427]

Our Hertz car (6S817) has been in the family for over 40 years.  The original block came with the car when we purchased it.  I'm in the process of collecting parts for it.  The block casting date is 5K23 and the assembly date appears to be 5L3.  There is an additional character at the end of the date code that appears to be a "T".  Anyone know what that could possibly stand for?

I have also located a set of heads that are date coded 5H23 & 5H26.  Would these within the accepted time frame for a proper assembly?

Thanks.

Roy Simkins
rsimkins@comcast.net
SFM6S817, 67400F7A03040
http://www.S-TechEnt.com/Shelby.htm

[J_Speegle]

The last letter in the pattern identified the worker (initial) that assembled the assembly

IMHO and looking at other Shelby and Mustangs assembled around the same time I believe Aug cast heads would be early for a November assembled engine.

[S7MS427]

Thanks, Jeff.

So what have you seen as a typical interval head casting to block casting to assembly date?

[J_Speegle]

So what have you seen as a typical interval head casting to block casting to assembly date?

Using later (to stay away from any of the start up/early supply possible issues) 65 through end of 66 production -  the records I have show

Heads dated -

Approx two months prior to engine casting - 14%
About one month prior to engine casting - 47%
Cast same month as the engine casting - 33%
About one month after engine casting date - 5%

Just used the month to figure the groupings above rather than count the exact day spread for all of the examples. Not scientific at all nor a large percentage of all the engines built during the time period used.  But what I can offer 

Hope this helps

[S7MS427]

Yes, it does help.  14% is good enough for me as I'm not going concurs with this car.  Thanks for the detailed response.

[J_Speegle]

Yes, it does help.  14% is good enough for me as I'm not going concurs with this car.  Thanks for the detailed response.

Guess I was focusing on the spread between assemble and head casting but as the evidence shows its possible and matches some of the other examples

Glad to help as always

[Hertz74]

I own #818,  bought in 1974..  overrides.  Numbers match engine,  don't know about the trans,  or rear en.  Its a driver 50 footer, have a lot of fun.   78K miles.   FYI do you have a metal hood


Chuck

[S7MS427]

Chuck,

817 also has overrides.  And over 100K miles.  It too is a driver and has a 50 year patina to it.  Yes, the hood is all metal.

I met you at Mid Ohio in 2016.  The following 12 Hertz cars were in attendance: SFM6S452, SFM6S555, SFM6S679, SFM6S817, SFM6S818, SFM6S1431, SFM6S1591, SFM6S1654, SFM6S1870, SFM6S1916 , SFM6S1938, SFM6S1963, SFM6S1964.

[outlawincorporated]

Chuck,

817 also has overrides.  And over 100K miles.  It too is a driver and has a 50 year patina to it.  Yes, the hood is all metal.

I met you at Mid Ohio in 2016.  The following 12 Hertz cars were in attendance: SFM6S452, SFM6S555, SFM6S679, SFM6S817, SFM6S818, SFM6S1431, SFM6S1591, SFM6S1654, SFM6S1870, SFM6S1916 , SFM6S1938, SFM6S1963, SFM6S1964.

S7MS427

It was certainly a impressive line up of 66 GT 350-H at that event. took many photos as i dont think i will ever see that many in one place and in one line again.

congrats to the people who co-ordinated that gathering

regards

PHILL BERESFORD
MELBOURNE.
AUSTRALIA.