Use the 55-58 rockers with the center groove intersecting the spit hole in the rocker.
Edit. Let me walk that back. What is the casting date on the block? The reason I ask is that the production line for 58 would have shut down like August or September, I forget which, to re tool for the next model year. For example, I had a block cast in like late july or August I want to say of 55. Shooting from the hip you would say its a 55 block but in reality it was a 56 block with the neoprene seal.
So if your block was cast in late 58, it may have been cast for the 59 model year, if so, then you use the 59 and up rockers.
Last edited by Dragsix; 03/30/2022 2:51 PM.
