Topic: Block casting date vs car build date?

[wsu0702]

I have been on the lookout for a date code correct 428 block for my 69 Mach 1 as it currently has a "C" block from a '68 full size car with a late '67 block casting date.  I found a seller who has a std bore 428 block with a March 26th 1969 casting date.  My car was built in San Jose on April 24th.  I am thinking that this block's casting date is probably outside of the reasonable range (too late) but wanted to get your opinions on this.

[sportyworty]

Many of the blocks have an assembly date stamp. This date is very often 7-10 days after cast date. I would check that first before purchasing in case it was an exception and assembled 3 weeks later for example making it not likely a good match. If you do not care about the assembly date and just want to know if 4 weeks is enough time then I would say maybe. Typically the San Jose cars have engine dates earlier than other plants due to the logistics and distance from The Dearborn engine plant to San Jose.  Engine inventory at the time your car was assembled would also have bearing on a time frame. Personally I would say it is tight but works. My Talladega was 6 days after assembly date closest I have seen and engine has never been out of the car so it happened. Your car was produced at the height of 428 CJ production when lots of inventory was on hand. Lots of casting batches and things were moving quick based on the production numbers compared to 68 or 70 CJ production. It is entirely possibly but you will need to compliment it with other close dates for a nice date match assembly.

[silvercat]

I may be a bit late on this reply but you may get a hint about the correct block date by checking the dates you have on each cylinder head shown under the valve covers and the intake manifold date at the very back of the manifold (hard to get at).  Although the harmonic balancer will not really nail the date but you could see what date it has.  It could be the balancer from the 8C block or the original block.  The balancer would be Month/Year (like C9 March 1969).  I dont recall if the date is before or after the timing marks. 

[J_Speegle]

.... The balancer would be Month/Year (like C9 March 1969).  I dont recall if the date is before or after the timing marks.

IF you look at the date coding article in the library it will show the date and location