I am not aware of anyone that sells brass front and rear "freeze" plugs for the 216/235 engine. Given the design of the plug (having to bend it to lock it in place), I am not sure brass would be strong enough to stay in place. Maybe they exist, I don't know. How long did it take the originals to corrode to the point of failure? If coolant is always in the system, it acts as a rust inhibitor anyway. Therefore, I would think corrosion to be non issue on a well maintained engine/cooling system.
