I did a pacesetter header, flowmaster 40 series muffler, 38 deges weber carb, pertronix ignition with hot coil, MSD 8mm wires, electric fan, gilmer pulley kit from:
http://www.tweakit.net/shop/advanced_se ... &Submit=GOand up graded 75amp alternator to keep up with everything. thats about it for now still need to rebuild the motor and port match and maybe solid motor mounts.
All of this made a significant difference, most of this done all at once. On my first run out off the garage I broke both of my motor mounts from the gains, that made me a lil giddy.