just took eng. out of may 40 merc. no big # out close to block ther is a one inch circle. inside at top of circle letter C at bottom eather a A or a 4.lrft side a 1. rt, side a 4. no other numbers. intake deck 99 stamped on rt. side left side a diamond with a v inside , # 1 v 4 . no other stampings. an to top it off. the clutch p p is surrounded buy a inch an one half ring that sticks out an id part of flywheel. about a quarter inch thick. HELPPPP. reguards dick t.