You never know what someone has done before so when I provide a pushrod for my mod which uses a needle roller thrust race in the outer plate I make up a 7.5" long pushrod. Harden one end and then fit that end in first so that the rider can cut it to length. If you do something similar then you can make it the correct length even if a previous owner has made a non standard length inner pushrod. Also I suggest that you use a quarter inch roller rather than a ball.