V6 Non-Balance Shaft Engines with Hyd. Roller Cam . Mild Street Performance - Slight Lope At Idle - Works with Stock Converter - For Carbureted Applications. Aftermarket Intake, Headers and 3.40 to 4.10 Gears Suggested. 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 cover is noticeably taller than the non-balance shaft version.