They are the dual o ring. Keven just shipped the motor friday, my frame is still at the powdercoat shop, and waiting for a-arms and swing arm to show up. The pipes look really good as far as finish but won't really know about fitment untill other stuff gets here. This is my first ground up build. Everything is down to nuts and bolts right now. Waiting sucks, but what you gonna do.The only original piece on the engine is the cases, the intake is a chariot I think, what ever HJR uses. +4 crank pistons, cub 68mm drag port, +5 timing plate adjustalbe,noss head wt 20cc custom domes vforce3 reed/cage 39mm carbs, 1-5 dunable override ndown tranny. pod filters, cases match ported to cylenders.Should be fun toy when completed !!!!!