I have a 66 coupe. I currently have a 302 that was rebuilt a couple of years ago and it sat. While being rebuilt we put brand new heads (351). Now we kept the intake (289). Runs pretty good, however it is smoking bad from the passenger side exhaust. We pulled the plugs and 2 are fouled. I believe (hopefully) that the rings may be stuck, but can oil back up into the intake causing the oil in the exhaust? Please HELP!