Radiator cap replacement for non stock aluminum radiator

Aftermarket AL rad is probably a Chevy spec neck. My Mazda takes a cap that is called out by Mazda to have the correct depth so it will vent properly to the overflow outlet and not vent out the cap. They are not all the same. I have a 67 spec Mustang Aftermarket AL rad in my '65 and they call out a Chevy cap too!