LS (LS2 / LS3 / LS6 / L92 ) Professional Flap Top: (standard Bore:4. ... " and 4.065". Rings:1.2mm 1.5mm 3.0mm) LS (LS2 / LS3 / LS6 / L92 ) Professional Flap Top:(standard Bore:4 ... Top,4.065''Bore, Rod lgth 6.125", Comp Ratio11.2:1, Comp.Ht. 1.115, -5cc Dome Vol,4032 alloyFlat ... Top,4.070"Bore, Rod lgth 6.125", Comp Ratio11.2:1, Comp.Ht. 1.315, -5cc Dome Vol,4032 alloy ...