Hi Ron, i sourced a rx7 mk 4 pressure plate and clutch disk for my project to go into a 016 box i had 3mm skimmed from inside the bellhousing and the clutch people changed the splined centre section of the disk to suit the input shaft, about 30 splines, i think the 012 and the 016 bellhousing are almost identical.
Pressure plate measures 293 and disk is 235 that was the biggest i was able to fit in the space the disk was made by valeo
regards
Graeme