R6 440 block?

Like this? Apparently..the 440 I bought isn’t just any old 440...it’s a 1972 R6 440 that somehow found its way into a 1975 Chrysler New Yorker.
It kind of explains all the peculiar characteristics I found as I was disassembling the engine..none of the info and pics I was seeing looked like what I had on the engine stand.

Can anybody tell me more about this R6 block I have?

After I saw NASCAR in the description I figured Yea fkn right..
But..it’s got all the described markings of an R6 block...right down to the year