A system of devices for introducing an interventional device into a carotid artery, the system comprising: an arterial access sheath adapted to introduce a catheter into an artery, the arterial access sheath including a sheath body sized and shaped to be introduced into a common carotid artery via a carotid artery access site, the sheath body defining an internal lumen that provides a passageway for introducing a catheter into the common carotid artery when the sheath body is positioned in the common carotid artery; an elongated first dilator positionable within the internal lumen of the sheath body, the first dilator having a tapered distal tip sized and shaped to dilate a needle puncture site to a larger diameter for insertion of the arterial access sheath into the artery, the first dilator having an internal lumen to allow the dilator to be inserted over a sheath guidewire into an artery, wherein at least a portion of the first dilator has a first bending stiffness, wherein the arterial access sheath and the first dilator can be collectively introduced into the common carotid artery; an elongated second dilator positionable within the internal lumen of the sheath body , the second dilator having a tapered distal tip, the second dilator having an internal lumen to allow the second dilator to be inserted over a guidewire into an artery, wherein the second dilator has a distal region having a second bending stiffness less than the first bending stiffness of the first dilator , characterized in that the system further comprises a sheath stopper slideably mounted over the outside of the distal portion of the sheath body for effectively shortening the insertable portion of the sheath body by creating a positive stop at a certain length along the sheath body . an arterial access sheath adapted to introduce a catheter into an artery, the arterial access sheath including a sheath body sized and shaped to be introduced into a common carotid artery via a carotid artery access site, the sheath body defining an internal lumen that provides a passageway for introducing a catheter into the common carotid artery when the sheath body is positioned in the common carotid artery; an elongated first dilator positionable within the internal lumen of the sheath body, the first dilator having a tapered distal tip sized and shaped to dilate a needle puncture site to a larger diameter for insertion of the arterial access sheath into the artery, the first dilator having an internal lumen to allow the dilator to be inserted over a sheath guidewire into an artery, wherein at least a portion of the first dilator has a first bending stiffness, wherein the arterial access sheath and the first dilator can be collectively introduced into the common carotid artery; an elongated second dilator positionable within the internal lumen of the sheath body , the second dilator having a tapered distal tip, the second dilator having an internal lumen to allow the second dilator to be inserted over a guidewire into an artery, wherein the second dilator has a distal region having a second bending stiffness less than the first bending stiffness of the first dilator , characterized in that the system further comprises a sheath stopper slideably mounted over the outside of the distal portion of the sheath body for effectively shortening the insertable portion of the sheath body by creating a positive stop at a certain length along the sheath body . <EOS>