Tilton 5.5" OT-3 Series Clutches and Parts
The Tilton OT-III is a very high-quality open style 5 1/2" diameter racing clutch. The aluminum cover is much lighter and stiffer than the stamped steel cover used on many competitors' clutches. A 5 1/2" clutch significantly reduces rotational inertia over a 7 1/4" clutch, improving acceleration and reducing crankshaft stress during gearchanges. The drawback is that disc wear is more rapid than with a 7 1/4" clutch, so you should be prepared to replace discs more frequently. Requires specially modified flywheel.
The OT-III clutch is only available with the high-strength Gray spring. This spring gives the clutch a rated torque capacity of 250 lb-ft (single disc), 500 lb-ft (dual disc), or 750 lb-ft (triple disc), but it also requires a great deal of force to operate. Cable actuation systems and external slave cylinder release mechanisms will not work with the OT-III clutch. A hydraulic release bearing (38mm bearing contact diameter) is required.