Vented Rear Rotor Conversion Kit The inboard brakes used on JaguarÕs brilliant I.R.S. keep unsprung weight to a minimum, but a trade-off is poor cooling. For track- or high-performance street use, the rear brakes can easily overheat. Many solutions have been tried over the years but upgrading to vented rear rotors is one of the best. After poor availability from our previous vendor, we have now developed our own kit which includes rotors, rotor mount rings, caliper center spacers, caliper mount spacers, parking brake forks and lock tabs, stainless steel caliper cross over pipes plus all hardware. Please note that this kit requires the use of Girling-style calipers as used on Series II and III E-Type. Owners of those later cars wonÕt need additional parts, but Series I owners can purchase the basic kit and source their own calipers, or purchase our second kit that includes calipers lovingly rebuilt in our restoration shop using stainless steel pistons and all new seals. This kit also includes new brake pads. Finally, there were myriad differential castings; when fitting later calipers to an early differential, some clearance grinding may be required on the caliper mounts to fit them to the differential, but there is plenty of "meat" on the calipers to do this safely. In addition, some earlier IRS "Cage" sheet metal have a small opening that must be enlarged to accommodate the larger, later, calipers.