  We present the preliminary results of a survey of the open clusters NGC3532
and NGC2287 for new white dwarf members which can help improve understanding of
the form of the upper end of the stellar initial mass-final mass relation. We
identify four objects with cooling times, distances and proper motions
consistent with membership of these clusters. We find that despite a range in
age of ~100Myr the masses of the four heaviest white dwarfs in NGC3532 span the
narrow mass interval M~0.9-1.0Msolar suggesting that the initial mass-final
mass relation is relatively flatter over 4.5Msolar <~ M_init <~ 6.5Msolar than
at immediately lower masses. Additionally, we have unearthed WD J0646-203 which
is possibly the most massive cluster white dwarf identified to date. With
M~1.1Msolar it seems likely to be composed of ONe and has a cooling time
consistent with it having evolved from a single star.
