273 rocker push rods

If you use the locking nut studs your going to have problems with them on a stock rocker. The top of the rocker where the stud goes through needs to be machined flat or the lock nuts will keep losing up. Crane studs with the Allen head is a good one to use if you go that route. If you want to stick with the iron rockers I would buy a complete set of new ones, with the locking nuts. Isky used to make them, as well as crane, how about comp? If this is a stock motor the 273 ones as is will work fine. I ran a combination of Isky and crane’s in a stock eliminator motor for years. I just took that motor out, they still look good.
The pushrod lenght doesn’t change your geometry in these motors, the rocker shaft to valve tip height does. About 2 threads out of the bottom of the rocker is what you want. It will give you the adjustment you need. If you have any questions pm me.