CORVETTE ENGINE SERIES NUMBER AND SUFFIX CHART Cont 1968 427 8 CYLINDER Type TYPE Description Designation Description Designation High Performance IL Special High Performance Tri Carb IR High Performance and Tri Carb IM Heavy Duty IT High Performance Tri Carb and 3Speed Special High Performance Tri Carb Automatic Trans IO and Aluminum Heads IU 3 Speed Automatic Trans IO 1969 350 8 CY LIN DE R High Performance HW Manual Trans HY High Performance C A C HX 3Speed Automatic Trans T H 400 HZ 427 8 CYLINDER High Performance 3Speed Tri arb Special High Performance Automatic Trans T H 400 Ll Heavy Duty Clutch LT High Performance LIVI Aluminum Heads Heavy Duty Clutch LU Tri Carb High Performance 3 Speed Heavy Duty 3 Speed Automatic Automatic Trans T H 400 LN Trans T H 400 LV Heavy Duty LO Aluminum Heads 3 Speed Automatic Aluminum Heads LP Trans T H 400 LW Tri Carb High Performance LO Tri Carb Special High Performance Tri Carb Special High Performance LR 3 Speed Automatic Trans T H 400 LX 1970 350 8 CYLINDER Manual Trans CTL High Performance Transistor Ignition C A C CTO 3 Speed Automatic T I l 400 CTM Special High Performance CTR High Performance CTN Special High Performance Transistor Ignition CTU High Performance C A C CTO Special High Performance Transistor Ignition High Performance Transistor Ignition CTP 4 Speed CTV 454 8 CYLINDER High Performance 4 BB L 35peed 4 BBL Heavy Duty 3 Speed Automatic Automatic T H 400 CGW T H 400 CZN High Performance 4 BBL CZU High Performance 4 BBL Transistor 4 BBL Heavy Duty CZL lngition CRI 1974 GM PARTS Dl ISION GENERAL MOTORS CORPORATION CHEVROLET P A 3OB 9