You can get resto parts from Yearone, summit or jegs.... And as far as performance parts for a 307 you need to understand the motor. It was only made for 5yrs (68-73) and in 68 wasnt to bad of a motor being rated at 200hp and 300ft/lbs as it was a 283 block with a 327 long stroke crank. 3.875in bore and 3.25in stroke. People often compare them to the 305 but in actuallity they are not. Not many people build this motor bc it still has a small bore so theres not much to go on as far as what kind of performance gains there is. A 72 307 is rated at a wimpy 115hp so its up to you if you just want to swap out the motor.