My sons and I are looking into doing drag week next year. We want to use the '28 Chevy roadster we're building. It will have a very basic 283. If it runs anywhere near 15's I'd drop dead. So from what I can tell from the NHRA rule book is that convertibles don't need roll bars until they run 13's but I don't know if that applies to roadsters. Here's a mock up pic.