GTO 8 Rib Drive Conversion Kit with 10% Overdrive. Harmonic Balancer

LS1 GTO 8 Rib Drive
Conversion Kit with 10% Overdrive Balancer

Part# 989
Only $1080.00

NOTE: Innovators West specific pin kit required when used with a stock non-keyed crankshaft.

8 Rib Drive Conversion Kit with 10% Overdrive Balancer for GTO. Conversion kit includes:
18338-Rib Drive - 10% Overdrive Damper
1979LS Truck 8-Rib P/S Pulley
11010GM 8-Rib Smooth Idler Pulley - Offset
1973GM 8-Rib Ribbed Tensioner Pulley
110318-Rib GM Alternator Pulley or 1089 Underdrive 8-Rib Alternator Pulley
Any additional aftermarket pulleys must be sourced from the manufacturer of those pulleys. Includes SFI 18.1 10% Overdrive Harmonic Balancer.


  • Dual Keyway Option - Add $20.00
    Add dual keyways for Supercharged or Extreme Duty Applications. Requires double keyed crankshaft snout.
  • LS1 - LS2 - GTO Crank Pin Kit - Add $75.00
    #967 Crankshaft Pin Kit for GM LS1, LS2 GTO. Designed for use with Innovators West dampers. For Stock Crankshafts Only.
  • Blower Hub Option - Add $25.00
    The super duty hub has increased material for supercharged applications.This increased material helps to protect the hub from cracking in high load applications. The super duty hub is recommended for supercharged applications making over 750 rwhp. Includes matching timing cover oil seal.

Application Notes


  • Cars equipped with a sprag style alternator pulley will need to purchase PN#1053 LS GTO 17mm x 1.5 nut for the alternator pulley.

  • This system was designed on an LS2 equipped GTO. The 2004 LS1 GTO's have been found to use a variety of different brackets, power steering pumps and/or alternators.


  • Exceeds SFI 18.1 standards and is marked on front with SFI Sticker, and on the rear with SFI number stamped into unit.

  • LS GTO 17mm x 1.5 Alternator Nut for converting OEM Sprag style to fixed pulley.