jrp
03-29-2004, 10:05 AM
Significant Gen III Engineering Points
• All Gen III truck engines use iron blocks. Only the Camaro (F-car) and Corvette (Y-car) LS1/LS6 engines feature aluminum blocks.
• All Gen III engines have aluminum heads except for the ’99 LQ4 engines that were equipped with iron heads. These engines received aluminum heads for the 2000 model year.
• All Gen III engines share common main, rod, and cam-bearing journal diameters for ease of interchange. All blocks use a cross-bolted six-bolt main cap.
• All Gen III engines are completely metric.
• All valvetrain pieces are completely interchangeable. The standard rocker ratio for all Gen III engines is 1.7:1.
• All Gen III truck engines use cast- aluminum oil pans that are deeper than either the Camaro or Corvette pans.
• All intake manifolds interchange. The truck intakes are roughly 3-4 inches taller than the passenger-car intakes.
• All Gen III engines employ reusable gaskets for all sealing surfaces except for the head gaskets. This makes it much quicker and easier to service the engine.
• There are only two intake valve sizes for all the Gen III engines. Exhaust valves are all the same diameter.
• Truck and Camaro engines use cable throttle linkage while the Corvette uses an electronic throttle. There are also some SUV engines with traction control that use an electronic throttle control.
• Bellhousing patterns are the same for all Gen III engines. The crank flange is basically the same depth as the bellhousing flange.
• The Gen III firing order has been revised from 1-8-4-3-6-5-7-2 to 1-8-7-2-6-5-4-3. Note that the pairings 1-8, 4-3, 6-5, and 7-2 remain the same, but the pairing order is different for reduced vibration.
• The valve angle on all Gen III engines is 15 degrees versus 23 degrees for the original and Gen II small-blocks.
• The Gen III bore spacing is the same as the original small-block, but each cylinder is ringed with only four head bolts instead of five.
taken from Chevy High Performance.
• All Gen III truck engines use iron blocks. Only the Camaro (F-car) and Corvette (Y-car) LS1/LS6 engines feature aluminum blocks.
• All Gen III engines have aluminum heads except for the ’99 LQ4 engines that were equipped with iron heads. These engines received aluminum heads for the 2000 model year.
• All Gen III engines share common main, rod, and cam-bearing journal diameters for ease of interchange. All blocks use a cross-bolted six-bolt main cap.
• All Gen III engines are completely metric.
• All valvetrain pieces are completely interchangeable. The standard rocker ratio for all Gen III engines is 1.7:1.
• All Gen III truck engines use cast- aluminum oil pans that are deeper than either the Camaro or Corvette pans.
• All intake manifolds interchange. The truck intakes are roughly 3-4 inches taller than the passenger-car intakes.
• All Gen III engines employ reusable gaskets for all sealing surfaces except for the head gaskets. This makes it much quicker and easier to service the engine.
• There are only two intake valve sizes for all the Gen III engines. Exhaust valves are all the same diameter.
• Truck and Camaro engines use cable throttle linkage while the Corvette uses an electronic throttle. There are also some SUV engines with traction control that use an electronic throttle control.
• Bellhousing patterns are the same for all Gen III engines. The crank flange is basically the same depth as the bellhousing flange.
• The Gen III firing order has been revised from 1-8-4-3-6-5-7-2 to 1-8-7-2-6-5-4-3. Note that the pairings 1-8, 4-3, 6-5, and 7-2 remain the same, but the pairing order is different for reduced vibration.
• The valve angle on all Gen III engines is 15 degrees versus 23 degrees for the original and Gen II small-blocks.
• The Gen III bore spacing is the same as the original small-block, but each cylinder is ringed with only four head bolts instead of five.
taken from Chevy High Performance.