440 motor block stamp

I have a mopar block stamped by distributor D4 blank then 0 . Positive there is no 4 by 4 just blank. Someone sid it could be a Nascar block? Any ideas. Thanks

Maybe out of a motor home. Lot of 440's where used out of them in a swap.

Good info here - https://www.440source.com/blockinfo.htm

Here is a picture of block

"There was a 440 nascar block, I've only seen one in my time. The 440 nascar block has a giant X cast, not stamped into it. You can't miss it. Its a thicker block with the water jackets moved slightly to allow for a full .10 over. They were used post 1972 after the hemi's were banned. They are extremely rare. most were scrapped after their racing days were over, however, there is one sitting in a muscle museum near Lexington, KY. I've got pictures of it somewhere.

That being said, I highly, highly highly doubt that is what he has. Simply because the 440 nascar blocks weren't out in 71."

https://www.forabodiesonly.com/mopar/threads/r6-440-block.306229/

Cast in '67 for a '68 model car, hence the "D". The 2nd "4" was probably very lightly stamped, or not at all.