plus 8 to May 31st 1988 = 2,981
also
plus 8 sports lightweight same date 19
3313 built 1988 to 2004 when production ended according to the Morganville registry (which may be correct)
so about 6250 less the 1988 overlap, 1988 was a poor year for plus 8 so 5 months of 12 would be about 65 cars,
Total (very close to it) would be 6,185
6,160 is the Morganville total so that looks close as well and may be regarded as definitive
Chris444