My '65 Dart is a mix of drive train and suspension components. Went tochange the front bleeders if the factory(probably 1973+) disc and found they are not the size , 3/8 and 5/16. The rear drums won't accept either a 1/4 or 5/16. These are self bleeders that I got from Russell. Is there an "off" size?

7mm (9/32") is between 1/4" & 5/16". 10mm is between 3/8" & 7/16"
Doug

as doug said, more than likely metric size. most aftermarket parts for the last 15yrs or so use metric fasteners, so i would try a metric size wrench or socket on your bleeders.