if the peps shock was originally for a blaster, it should use the stock bolt which is an m10 x 1.25
i'm not sure of the length, you could measure that easily, allowing enuf threads to stick past the frame mount with room for a nut, + a few extras.
your problem is going to be finding one with enuf smooth shoulder for the shock eye to run on, and threads only past the mount.
i may have one laying around ?, as i've done 3 KOR shock bushing conversions, which take an m12 bolt