Rebuilt 302 casting heads available through Rockauto
FWIW #2, here is a 2.02" intake mocked up on a standard bore 273 block; a piece of white paper with a 2.02" diameter was centered and glued on a standard valve; you can see how much it interferes.
FWIW..... I did some work on this..... and your supposition is right. With the standard valve spacing and the Magnum valve diameters, the spread across width of the valves is 3.635"..... a bit larger than the standard 273 bore. And since the valves initial enter the bore not quite at the full width of the bore, then its almost certain to need some notching even with an overbore of .030" or .040" ... and then you run into the issue of limited lift before the bore notch gets into the top ring travel in the bore. So.... not without some work and limitations, or a big overbore and offsetting the bores towards the intake side.
FWIW #2, here is a 2.02" intake mocked up on a standard bore 273 block; a piece of white paper with a 2.02" diameter was centered and glued on a standard valve; you can see how much it interferes.