If you must go to a carb, replace the distributor with a vacum advance , HEI type, (found on small blocks from about 1980 to 83 or in JEGs or other aftermarket catalogs for around $150.00.) Add 12 volts and you have all the spark you need and replace what fuel system you have with a simple intake with a carb and you're down the road. Performance wise, you may be better off to work with what you have, but if you really want a carb setup, which was the question, this formula is the simple way to do it:
HEI/Vacum adv Distributor + carb =good running sbc.
Hope this helps.