... Flap Top: (standard Bore:4.000" and 4.065". Rings:1.2mm 1.5mm 3.0mm) LS (LS2 / LS3 / LS6 / L92 ) Professional ... Top:(standard Bore:4.000" and 4.065". Rings:1.2mm 1.5mm 3.0mm)Flat Top,4.005''Bore, Rod lgth 6 ... .125", Comp Ratio11.6:1, Comp.Ht. 1.115, -5cc Dome ... 070''Bore, Rod lgth 6.125", Comp Ratio11.0:1, Comp.Ht. 1.115, -5cc Dome Vol, 4032 alloyFlat Top,4. ...