So I threw a rocker on my 325is I had an old 325e head sitting around but realized it wouldn't work so I got another 325is head took it to the Machine Shop and they asked me if I had another cam I told him that I do but it's out of a 325e they said it shouldn't make a difference now my car won't stop running rough it when I come to a stop it almost dies I need to know if anybody has any experience with this and I just noticed that I think the cam gear is different but does anybody know how much different