Hi, a friend just rebuilt a mechanical E7 350.This man is a fine mechanic who has an excellant reputation of being the best.He did an inchassis with piston and liner kits, rod and main brngs, pump and injectors and rebuilt heads. When the engine brake is turned on it works fine but when it is shut off one cylinder on no.1 head stays on until the oil pressure drops.He changed the dynatard solenoid, still did it. Thought maybe an exhaust hydraulic lifter was sticking,went thru and reset.Switched complete rocker from front to back, problem stays in front head. will do this when brake is manually