I dont have it apart yet,im assumeing the area before the fire ring thats not really doen any thing? i do have a set o 65 273 heads off another motor in the shed & they are rite @ 3.90 dia.
You have probably already checked to be sure that this other set of 65 273 heads has the same intake bolt angle as the ones that were on the engine.:thumbup: Maybe not. :thumbdow: If they don't match be prepared to use a different intake manifold.
