22-inch Replacement Rad. for six cyl.?

I have the oem 19-inch core unit and it cannot handle ambient temps over 95 f. I could have the core tested and maybe replaced but am also considering upping to a 22-inch core unit. Of course the inlet and outlet pipes need to be in same location for both cores. Has anyone done this swap and if so, what are the sources? Rad would be black and not aluminum. thanks.