Centerforce part number (700170) is a steel 153 Tooth GM/Chevy flywheel for use with 1986 and newer (non Gen3) engines with 1 piece rear main seals. It features a 153 tooth ring gear and weighs approximately 31Lbs. with a 12.75' diameter and caries a SFI 1.1 safety rating.
From the manufacturer:
Centerforce manufactures the best in SFI-certified performance flywheels. These flywheels are CAD/CAM designed and CNC machined to strict tolerances for perfect fitment and hassle-free, bolt-in performance. Centerforce flywheel part numbers with a "700" prefix are made from billet steel and match closely to the original equipment flywheel weight .