Could be. There are 2 types that I know of. The thin ones that I associate with early engines and the tube type ones that I've seen on later emgines. They are the same length, the only difference is in the size of the cup at the top that the adjuster screw fits into. These are different from each other. That being said if you take hime 2 push rods and 2 nuts and screws from your rockers everything should interchange and work just fine. You don't want to use the wrong adjusters on the wrong push rods, the rods will break fairly soon. Don't ask me how I know.

54Monster