[MARKDTN]

IMHO-headers and big exhaust are a waste on a 307 (and even stockish 350s).

I might suggest a different route. If you are open to fuel injection, put Tuned Port on top of your stock 307. Lots of low end torque. Simple, reliable. Works great with stock cam. TPI units are cheap now. Lets say $200 unit with distributor, $150 Injectors, $30 ECM, $100 PROM, $200 wiring (or make your own from a 3.1 Cavalier or Corsica-or F-body or Corvette), and $100 fuel pump. So $800ish swap (maybe much cheaper if you find someone removing a TPI engine to go LS) and leave the drivetrain alone. Just a thought.