All those type seals are design to be fitted, pressed onto a certain size O.D. valve guide boss, they come in 3/8,11/32 and 5/16 guide sizes as well as miilmeter for the other type motors.they come in multiple inner I.D. also, .629,.530,500 and several different O.D. on the seals so they fit into the inner valve springs sizes. They usually have a plastic sleeve for installing them that goes over the keeper grooves so they don't get torn up.
I buy them from Goodson, maybe look there for yours scope
Good luck and Merry Christmas thumbs

Last edited by Cab_Burge; 12/25/17 09:31 PM.
Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)