You can do it yourself in about 10 minutes, with a HEI re-curve kit from the local-yocal parts store. Use the light springs, should get you close.
Take the distributor out, take out the screws in the housing that hold the baseplate, take a thin nail or something and knock out the roll pin that holds the shaft at the bottom plastic retainer, wiggle the plate up, unscrew the vacuum advance, remove it, and then slide the whole assembly out so you can work on it comfortably.
I'd say 16-18 initial, 32-34 total by 2500RPM, then plug in vacuum advance to a ported source and total timing should be around 50-52 max for best economy .
It will feel wayyyyyyyy more responsive.