Pics to compare. I could not find any visible differences EDIT scratch that..after further review, heads appear identical. Block very similar but water pump inlet and outlet closer together. timing belt tensioner looks the same but mounted at a more upward angle. timing belt pulleys both look identical. oil pump pick up on other side so oil pump not same.

In short. Same heads but small differences in block.

bottom line, its probably a good source for used heads and lower and middle intake (dreaded butterflies). worth further looking into.

http://engineguy.com/1996-94-mitsubishi-3-5-l-engine-6g74-atk251-vin-m.html

http://engineguy.com/05-03-kia-3-5-l-6-cyl-engine-g6cu-35d-atk261a-vin.html

The kia guy that came in here originally stating this was laughed out of here. But I think he was mostly right. Same heads and the block is very close.