Where to get 273 Head Gaskets?
A photo of the vintage 273 gasket set mentioned above. The label says for 64-65 Dart and 64-66 trucks. It probably predates the 318. The bores are 4.064"D. Of course, someone may have switched head gaskets, but seems unlikely. The box had been opened, but probably only to photo for ebay. It has the correct multiple exhaust gaskets and thick rubber seals for the ends of the intake manifold, unlike a later gasket set I have.
This satisfiies me that we aren't compromising by using over-sized gasket bores. I am a Mech Engr who did combustion experiments in grad school, but doubt anyone could make predictions without testing. The worst effect of an air gap is probably increasing unburned HC. I suspect insignificant for performance, but slightly increased emissions. Of course, if the gap fills with carbon, as some noted on rebuilds, that could be beneficial by providing a hot spot to promote ignition in the corners, if not too hot to cause pre-ignition (knocking).
A photo of the vintage 273 gasket set mentioned above. The label says for 64-65 Dart and 64-66 trucks. It probably predates the 318. The bores are 4.064"D. Of course, someone may have switched head gaskets, but seems unlikely. The box had been opened, but probably only to photo for ebay. It has the correct multiple exhaust gaskets and thick rubber seals for the ends of the intake manifold, unlike a later gasket set I have.
This satisfiies me that we aren't compromising by using over-sized gasket bores. I am a Mech Engr who did combustion experiments in grad school, but doubt anyone could make predictions without testing. The worst effect of an air gap is probably increasing unburned HC. I suspect insignificant for performance, but slightly increased emissions. Of course, if the gap fills with carbon, as some noted on rebuilds, that could be beneficial by providing a hot spot to promote ignition in the corners, if not too hot to cause pre-ignition (knocking).
