[1965 Pontiac Parisienne]

Hi,
i own an 1965 Bonneville with single master cylinder.
I`m just replacing with an dual 1967 Power brake master cylinder for drums.
Need help:
Which adapter size comes to the brake line for the rear drums?? (RH)
9/16 and female 1/4 .. i have 1/4 brake lines
the front adapter is a little bid smaller than the RH adapter for the rear drums ..
Any idea?? They are different .. LH is writting on the plastic pug 1/2 and RH 9/16

This: Item number: 230643468641
BRAKE LINE ADAPTER MASTER CYLINDER 9/16 18 X 7/16 24 ???????????
thx , Bjoern