These 3/8" thick pickled & oiled mild steel plates are precision laser cut to adapt stock, early style Energy Suspension urethane Chev insulators to the LS block. The large slot provides clearance for the reinforcing rib on the insulator preload plate (Energy Suspension wants the preload plates used!). Stock style rubber insulators can also be used, but you'll have to flatten about 1/2" of the top portion of the rib with a hammer for clearance.
These adapters let you put an LS engine on the stock mounts that were on a side-mount small block frame. The engine will be mounted in the same position as the original small block Chev.
Sold in pairs (driver and passenger side plates) complete with metric hardware.