<VV> Brake Drums

[Paul Nail]

I have a 1963 Monza 900 coupe.  I am going through the brakes completely,
master cylinder, wheel cylinder, lines, linings etc.  The shop manual says to
knock out a segment of the brake drum to remove them as there is no adjustment
hole on the backing plate.  I can't seem to locate the area to be knocked out,
usually on something like this there will be a casting mark to indicate the
section to be removed. Help!  P.A. "Rusty" Nail

1963 Corvair Monza 900 Coupe