radiator question

I need a radiator for my 78 Fury. was hoping someone had a copper/brass modine or something like that around but most everyone wants to sell me a Toyota looking POS plastic tank/aluminum core thing...
I found a couple places online that offer a 100% aluminum, tanks and all one for it. Radiator Express has a 100% aluminum TIG welded 2 row "heavy duty" one for what seems a good price, salesman says made in USA and lifetime warranty.
My question is this/ I am leaning towards that solid aluminum one, certainly do not want the plastic tanked POS even though it is $100 less.... but now I am adding in another different metal to the mix. The dash ahs never been out so the heater core is still the original copper/brass one. With a cast iron block, heads and intake, copper and brass in the heater core and now throwing an aluminum radiator into the mix. Will I have to worry about a reaction between all these different metals and something getting "eaten" away, like boats whose steel hull gets eaten away (that's why they attach hunks of zinc on them so the zinc gets eaten rather than the steel) they offer some kind of zinc petcock for an additional $18.95 that they claim to "sell the Hell out of" but made no mention of it being mandatory for the warranty to be good, etc... Any thoughts?
Author: volaredon