440 Engine Pad Decoding

[Dodge Don]

I ran across a 70 440 block that has an oddity I cannot decode. The casting number is the right 2536430-8 but on the pad itself it reads:

F440       Upside down "C"

3   4           HP


The engine appears to be a 70 Six Pack. The engine needs a rebuild, block looks untouched (other than being torn down) and has the six pack crank and connecting rods. That and the engine shop that has it says it came from a six pack car. The engine was dropped off for a rebuild awhile ago and work started but then divorce hit, couldn't pay the bills and forfeited the engine block in lieu of payment.

What does the upside down C mean?

Thanks.

[Ghoste]

A regular "C" means special crank and pistons but I have no idea what an upside down one is.  Just stamped in the wrong position?