Jegs sells several headers, one set lists 1964 to 1981 - 326 to 455 Gran Prix, Tempest, GTO and Firebirds. If the 1968 Gran Prix is pretty much identical to the 1968 Bonnevilles and Catalina’s, GP’s have hidden headlights in 68, virtually everything else is the same except some luxury options, then wouldn’t it stand to be true that those headers will fit the ‘68 Catalina? Is it that Bonneville and Catalina is not typically a car that gets modified therefore they’re not listed but will fit, or is this just wishful thinking?