COMP Cams Camshaft Cv6B 280HR-10V6 Balance Shaft Equipped Engines. Limited High Performance with Rough Idle Needs Intake, Headers, 2500+ Stall and 3. 73 to 4. 10 Gears. Adjustable Valve Train Required For Carbureted Applications Balance shaft equipped 4. 3L engines were introduced in '92 but GM continued to produce the previous version until '94. Non balance shaft 4. 3L's (' 85 '94) shared their timing cover with the small block Chevy V8 engine. The balance shaft 4. 3L's timing