Timing marks?

["James Lea" <clocks@midcoast.com>]

I got out my trusty timing light today in preparation for timing the BT7 but
there doesn't seem to be any marks on the wheel except the TDC mark. I know
that it is supposed to be set at 15 deg. at speed and 10 deg at 600 RPM but
with no marks to go by, I am confused. Were there marks that have been lost
over the years or were they never there and I am supposed to guess. Thanks for
any advice forthcoming. Cheers, JL

James Lea Pres.
MMSCC
Rockport Me. 04856
1962 BT7 II