Straight from 2014 rule book guys...
All front-wheel-drive or transverse-mounted applications using a clutch and running 11.49 or quicker, for which an SFI Spec 6.1, 6.2, 6.3, or 9.1 flywheel shield is not commercially available, must be equipped with a flywheel shield made of 1/4-inch minimum thickness steel plate. Shield must surround the bellhousing completely except for area of bellhousing adjacent to differential and axle shaft. Shield may be multi-piece, with pieces bolted together using minimum 3/8-inch-diameter Grade 5 or M10 class 8.8 bolts; may be attached to engine and/or bellhousing.