I bought a universal bcool radiator for my 66. it did not come with mounting hardware of any kind. i bought it because the car specific model was $600. this one was only $180 brand new.

So, the core support blocks about 3 inches of the radiator on either side, and because of the way the core support is made it pushes the radiator about 1 inch off the support. is it a bad thing to trim the material off of the support to get it to setright and get proper flow. i know that it is a structural part of the car. i dont need to remove much but i wanted to know if it is a common thing?

 

Mods to make the rad fit is not a big deal. It is structual but like you said, it's not much metal to remove or mod to allow proper fitment of the rad. I think it would look better if the rad fit properly so I would mod the rad support as needed. Just be mindful of cutting, you obviously don't want to cut out the entire thing, etc. Someone had pics of their procedure of this same type of thing, but that was before or during the site chaos of operations. I'm sure it's gone. Good luck!