i have a 97 dohc eclipse with a cracked head do i need to retime it if i change the head of the engine ?

If you have to ask this question, you don't have the knowledge, or specialist tools, to do the job yourself. Take your vehicle to a workshop and pay to have them do it right, the first time, otherwise if you attempt to do it, it will end up in a workshop eventually, and end up costing more than it should have,

Of course you will. Replacing the cylinder head involves removing the cams and other related gear and replacing them on the new cylinder head, so they will have to be retimed. It's a basic part of putting things back together.

the correct term is cylinder head

and yes but to make it easier leave timing marks because you will need to crank it backwards to loosten the belt and change the belt while your at it the last thing you want is a new cylinder head with ****** valves if the belt brakes good luck hope this helped

yep