The radiators you have listed are 26" whereas the ones for a 72 Imperial and in fact most later Imperials are 28". Spectra probably doesn't make a complete radiator in the 28" size, but maybe. The Spectra ones listed therefore won't bolt up to the present holes. Even if they did though, I have found that the aftermarket radiators are lousy at cooling since they are made with poor density fin spacings in the effort to maximize profit. Including Spectra. And aftermarket radiators such as Modine that advertise heavy duty or 4 row etc, still have lousy fin density and won't cool despite their claims. Ask me how I know....................
The only way to go is to have an aftermarket high efficiency core made up for your radiator by a radiator shop in your area (unfortunately, they are not so prevelant anymore), and that way you get to keep your factory top tank, lower tank and mounting brackets as well. You just need to be prepared to pay around $500 for a high efficiency core, because that is what it takes to keep these beasts cool in hot weather with the a/c on. You must seek very high density fin spacing, high efficiency cores, or your money is wasted, in my experience here in California. I have had such cores from Craig used in my radiators in the past, but there are a couple others out there as well. If you compare your factory core to the aftermarket radiators, the factory cores most closely match the high density cores, not the usual aftermarket junk.
