To answer the post made by member srt earlier in this thread:
In 2003 I was in contact with Willem Weertman when trying to find out more about the claimed "high nickel fuel block" of the early 70s.

He gave a long reply that I partly quote:

All the Hemi blocks from the first blocks cast in 1963 to the blocks now being marketed through Mopar Performance have essentially the same metallurgy, which contains nickel.

Chryslers Indianapolis Foundry was the source of all Hemi blocks until the Street Hemi was discontinued in 1971. During this 1963-1971 time span, Indianapolis Foundry was the source of all production V8 castings.
The iron metallurgy was exactly the same as all the high volume V-8 Engines. Chryslers block iron was already a nickel-alloy iron, the nickel level being slightly higher than other auto companies block iron.
Unlike the high-volume V-8 blocks, all the Hemi block castings, including the Street Hemis, were given an annealing treatment for stress relief. This is noted in the SAE paper 660342, "Chrysler Corporations New Hemi Head High Performance Engines".

After the Street Hemi went out of production, Mopar Performance took over the after-market Hemi block business. Other, small-volume speciality foundries were used and very slight Changes in nickel content did occur - within the Material Standard acceptable limits.
If the nickel got a little too high, complaints would come from the tool shops machining the Mopar blocks and from the race teams that the blocks were too hard and were difficult to machine and hone.

Nodular cast iron (also called ductile iron) was never used for any block casting, not even experimentally. However, nodular cast iron has been used for the bearing caps except on some of the first Street Hemi Engines, which used grey iron.

Starting in February 1970, the bulkheads of all blocks were thickened. Your date of Jan 19, 1970 sounds OK.

Soon after Mopar Performance started furnishing blocks, they brought out a siamesed-bore block that was stronger, heavier and allowed larger bore sizes, up to 4,50 inches. This was called a "Fueler" block at the time. Shortly afterwards, aluminum blocks by Donovan Engineering and Keith Black became available and the fuelers switched to aluminum almost 100%.

Mopar Performance continues to offer a non-siamesed "Street" iron block and the siamesed heavier block in the 2002 Mopar Performance Parts Catalog.

I have no information on specific test results using nitromethane. I recall the work was done to generate a spark advance calibration. In all probability, the test engine used stock Street Hemi block. There was no design investigation regarding the block´s ability to handle higher cylinder pressures.

In a second reply he also says:

In looking over the notes I made when talking to Larry (Shepard), I noticed he told me when the casting was changed in February 1970 to the heavier webs, Mopar Performance called the new casting a "Fueler" - to distinguish it from the prior casting. Later, when the siamesed bore block was added, the siamesed block became the fueler and the carry-over block became the Street.


To return to the original subject of the thread:
All Hemi D5 blocks I have seen, casting numbers 3577430-1 or -2, have the casting date 1-19-70.
Was only one batch made?