My wife's HPOCF '70 Camaro is in need of a muffler. Her's is a 307 w/single exhaust. I've tried NPD, Ecklers, Camaro Central, and ebay, and they only offer a complete system and only for duel exhaust, not single. I've also tried looking at Walker and a few others and none of their mufflers are the correct size, mostly way too short. Any suggestions?