just recore it and be done with it......with the money you will spend on a new one you would only be about 100 short for a recore. recores are way better than stock, with bigger tubes and more rows of tubes to boot!
You can buy a brand new one with a life time guarantee from Advance Auto for $209.
I am running one of the Advance Auto Ready Radiators in my 68 Barracuda. It is a 22" 2 core heavy duty unit and with a stoutly built 360 I have no cooling issues at all. And with the life time guarantee I will never have to pay for another one.
I would not worry about a 3 core unit. The factory 340/360 v8 AC radiator was a 2-core.