I wouldn't think of putting anything in except the correct radiator. You may have to rig something up to get it in. The shroud may not fit, right, the gaps may be off, it may look crooked etc etc etc etc Size does matter.
I don't know about "making a special bracket" to fit your 67. I'm sure you could make just about anything fit if you really wanted to go through the trouble.
I do know that the original radiators in the 1st gen Camaros have a very unusual bracket to mount the radiator to the support. They are not like a lot of the cars today that have radiators that just sit on a rubber cushion with a hold down bracket on top. The Camaro radiators have brackets attached to the sides of the radiator tanks that bolt directly to the car.