For '87-'94 GM 4.3L/262 cid 90. V6 Non-Balance shaft Engines with Hyd. Roller Cam. Works with Throttle Body and Sequential Port Injection with Aftermarket Chip. Good Low End and Mid-Range. Adjustable Valve Train Required. 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.