Shift418

New to the forum and thanks in advance for any help. I'm trying to mate a Z6 head onto a Y8 block. I presumed it would bolt right up, but apparently it doesn't. Any insight into making it happen?? Also, any other "issues" I may encounter and it's fix would be appreciated. Not sure anyone else has tried to do this but I'm at a standstill now. Reason for swap, I got the block in nice shape and my head has had some extensive work, plus I figured I wouldn't need to change to OBDII.

Any help or insight would be more than appreciated!!!!

Thanks much and have a great day!
Tom