Couldn't find any good pictures but Bell intercoolers had this ...

What are the variations in core construction used in intercoolers?
The variations are in the style of manufacture of the core material. A “Bar and Plate”-Style Core is made by brazing up a layered structure of flat plates separated by small rectangular spacers. A “Tube and Flange”-Style Core is created by extending a series of tubes through a header flange and brazing the assembly together. For heavy duty applications, pressure spikes up to 250 psig and rugged environments, ”Solid Extruded Tube”-Style Cores are available.