what is the difference between my mercury 502 block casting # 14096859 and a regular 502 block? I am looking at buying a brand new block, but all I can find is automotive blocks. Is there a real difference in block design and material. I have heard that my block is heavier than a normal auto 502. does anyone know where I can find another block like mine? New or used? Thank you in advance.

there is no normal automobile 502 as none came with them.
double check, but it looks like your's is a gen v 502 block.
14096859 Big Block V8 502, 4 bolt, Generation V

Gen V marine 502

I thought there were some 3500 series trucks that had 502s (8.2 liter) around 2008-2010. No?

No, 496 8.1 liters were made in the early 2000-2006.

Part is 14096859 Big Block V8 502, 4 bolt, Generation V

nope.

if there where, there would be lots more black stripes down your roads. lol.

So, will all of my internals will fit in a Gen VI block? Rotating assembly, crank, rods, and pistons. Also the lifter and pushrods? I know a Gen VI block has a 6 bolt timing chain cover and mine is a 10 bolt cover. but other than that, can I put all of my rotating assembly in a Gen VI block? I would like to use a Gen VI block as it is stronger as i understand it.

Thanks in advance,

yes, rotating assy will work fine in a gen 6 block

Yes........^^^^ the gen VI uses a step nose cam design and a retainer ring that keeps it from walking around, dont think the gen V is like that.