I've been running these for about ten years and do like them a lot. My exhaust is a bit of a problem though. In a 64 Fairlane, there just aint a lot of choice for headers. Hooker, Dougs, and one other make some for it but they are way spendy. Throwing the p's plug angle into the mix makes for header removal to change one of the plugs. Consequently, I am running HiPo cast exhaust that has been port matched to the heads.