thanks denny w.......i only presumed the spring seat would have been the same.........having never run them before, or rebuilt any until now. Learned a lot today thanks. I am going to put them on and check when the heads are on......From what I have read so far it makes sense to run them on a street motor. my only concern now is the lift.....if they clear great if not then I have to shim them.......what was the average lift you ran when using the rotators......I know about .500" lift will be too much but I'm at a conservative .471"......think they will be ok?