Ok I have the stock motor that come out my CRX 91 SI. Ok I want to know, to make sure. I can put a ZC head on the si block right???? Ok and I don't know if I want to go with the SOHC or the DOHC. Right now I have a DOHC in my CRX. But I think I want to try the SOHC out. Cuz I got a pal that has one in a 91 HB and he likes it. So tell me what you think??? Thx