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3.3.2 Roll Bars
Roll bars or roll cages are strongly recommended in all cars. A roll bar meeting the requirements of Appendix C, or a roll cage meeting the requirements of Section 18 of the General Competition Rules (GCR), is required in all A, B, C, and F Modified vehicles, and all open cars (see definition section) in Prepared Category and in D Modified and E Modified. The intent of this requirement is that all open cars using racing slicks must at a minimum have roll bars which meet Appendix C, regardless of Regional variations in category definitions and/or preparation allowances. For open cars in the Stock, Street Prepared, Street Touring, and Street Modified categories, the roll bar or roll cage height may be reduced from Appendix C or GCR Section 18 requirements to the highest possible height which fits within an installed factory specified hardtop or convertible top.
Its all in what class you run