I've slapped many of them into late model cars and not had any issues. As far as the older ones, I prefer the alum Griffin by far- great fit, appearance, and most of all they cool pretty darn good! Last summer I stuffed Griffs in a '40 sedan, a '65 fastback, and a '59 Fairlane- all still cooling just fine.
Buckle up- I wanna try something!!