You about to get a rebuilt MC to get a tailor made one but have the counter guy at your parts house cut a snip of vac line the same length as the machined recess at the end of the pushrod. They are virtually identical & will safely function fine. I forget the dia but just give him the pushrod & have him go back & use the roll of line that is a tight fit on the round nub (you only need a fraction of an inch for length). Cut a slight groove in it lengthwise end to end on the outside for air to excape as it locks into the piston blind hole for a good secure fit