MGA Part Numbers

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MGA Part Numbers - ATC4257
Wheel stud, MGA Disc wheel front (1600, 1600-MK-II)

PART NO.  SPL.PAGE  DESCRIPTION                                                           
ATC4257   16.K.1    Stud -wheel - (8), disc wheels -(front axle and suspension, 1600 and
    1600-MK-II Std.model)

Wheel stud, disc wheel front hub, MGA 1600, 1600-MK-II

Sorry about the brand name publication, but it was the only picture I could find.
The good news is, it looks like NTG may have the part, when no one else does.

For more reference information, see Replacing Wheel Studs WL-103