I know that the ZC engine has more horse power than the 88 integra's in America but what makes it so different?

 

Everything. Cams, pistons, intake manifold, etc.

It also depends what ZC you are compairing it to. The '88 D16A1 is basically a pussified browncover with blackcover electronics.

And no, it's not something you want to put in an '89 CRX, if that's what you're after.

 

The Integra engine only bolts into the 3G chassis, not the 4G. It's a pos engine anyway.