Yes, the HO timing. We just built up a mild street motor for my son's Fox mustang. Sounds very much like what you are trying to do. E-303 cam, Performer RPM intake, mildly ported E7 heads, 600 cfm carb. We just put it on the chassis dyno and made 256hp to the rear wheels. Will probably get a little more out of it when we finish tuning.