The cooling of the engine depends on heat transfer at the radiator. I believe you're right about aluminum transfering heat better than brass, I doubt that it is more durable. You won't see it in air conditioning units made for salty environs. But brass and copper do a darn good job of heat transfer too. The last two or three failed radiators I've seen were aluminum and plastic. I would never buy one to put in a Jeep unless it was the only option. If you need more cooling get another core. (3 or 4) <img src="/forums/images/graemlins/cheers.gif" alt="" />