360 in a 75 Roadrunner

I have read multiple post regarding a question of more power but my questions are a little different. I have a 1975 Roadrunner with 39000 original miles. It has a 360 with a stock intake and a 600 cfm thermoquad. (I think) it is a TQ though. 3.21 stock gears with a 340 stock automatic cam. It has dual exhaust but I would like to get more 0-30 performance. The car is strong after 30+ but as it being a very heavy car it doesn't have much off the mark performance. So I have thought about different rear end gear but keeping some sanity on highway speeds. It has also the stock heads and so wondering what all of you would do? I have read about different torque converters but I am a little confused on that subject. The car is original and it is only street driven. I know everyone here has a lot knowledge and experience so open to suggestions. Thanks everyone.