Ok first off I just bought a 90 CRX si. It has a SOHC ZC motor and I was wondering what I should do about changing my head. I was told that I could get a DOHC ZC head and it would fit, but im not sure. Or should I get a Vtec head, out of a D16z6? If you can Help Plz post.

you can't mate DOHC parts with SOHC parts. Slap on a SOHC vtec head.then you will have and pretty strong engine to build.