They are made by Harland Sharp for Mancini and cost $512 for the kit.
fast69plymouth said in a previous thread that they are close in length to the $908 set that Harland Sharp makes for use with Edelbrock (and Trickflow, Sidwinder, Promaxx) heads.
The mancini rockers do not come with the HS hardened shafts (the ones with the screw in plugs on the end) - they come with a set what looks like to me the Mancini Chromed shafts - definately not the HS shafts - overall the entire kit form mancini is a nice budget rocker for a solid tappet cam
