Used US Radiator many years ago for my 72. Upgraded to a 4 core with stock mounts. Fit like stock and cooled well. Rad is still good, though I am not using it in my current build. Copper/brass style. I am making plenty of changes. Maybe I should keep instead of the aluminum LS replacement I got from a forum vender? Had to revert to 3 row mounts to use the new one. Brass/copper is actually a better heat conductor than aluminum. A link to the site
https://usradiator.com/