Classic Mini short clutch flywheel strap bolt.
There are 3 of these shorter 5/16"unf bolts holding the spring straps to the flywheel on diaphragm type flywheels only. Not for Verto flywheel. Only tighten these bolts up to 16lbs per sq foot torque when using shake proof washer or 18lbs if using flat washer and locktite.
(MWA2A3659).