Just finished replacing head gasket, valve job, arp head studs, adjustable exhaust cam (still at 0), and BC 264s. Fired right up after the job, but has had a little bit of a rough idle. I've now run it over 30 minutes on three separate runs and the check engine came on with p300 plus 303-306. That said, my secondary ignition looked like crap putting it back on (coils, wires, and plugs), and all the clips were broken. What are the chances it's just secondary ignition? What's interesting is that cylinders 1 and 2 didn't seem to show codes at that time.