Need big block help

I'm new to BBC (been SBC for life to far) and I'm trying to sort out a friends FiTech system. Also trying to figure out his engine. He thought the shop built him a stroked 440. They called it a 501. I found 246 8330-M on the block casting number. My research keeps coming up the block was born as a 426 Hemi.

Now my question is, it has AFR EZ 440 heads on it. Can a 440 head be bolted to a Hemi block? Is this common? The M doesn't show in the charts, what might that mean?

I also found G111 482XAB on the pad at the water neck. I'm still searching for the numbers by the starter. I think the cast date is dec 71.?

Is this combination possible,,, Thanks Larry I'll take pics if that'll help but we're not going in too deep for now.