ANY of the more traditional SLR's OM1,2, Nikon F,2,3 Canon FT,FTb,F1,AE, A1, AV etc fire the flash when the first curtain fully opens the film gate.
The reason you may have a partial picture is that at higher then sync speed the shutter becomes a traveling slit and the Gate is partially covered when the flash triggers.
The cameras with electronic controls have the flash repeat at a very high rate so the ggate is covered by repeating exposures.