they say the alum rad with the alum/epoxy core works like a heat sink and is hard to fix if leaks at the core. they say. the same thing about copper brass lead rad with the lead working like a heat slink to. the they would be becool. there core is all alum and not set in epoxy .becool do make a kit for the 55/57 and there is other makers to .alum is nice has the look .but i have cooled things with copper brass that even the becool guys would have a hard time with